I recognize that this is a slide thread because of the GT thumbnail and low effort OP question, but regardless I think it's effective. The main controversy is whether or not the added spin speed actually helps terminal performance as they claim. They did some shady stuff with gel tests to make their round look a bit flashier for the camera -- stuff like water splashed on the block, so some people dismiss it, but having seen other gel tests I'm quite impressed at how well the cavity follows the spin of the round. Additionally, I've seen barrel length tests that show that speed drops off very quickly with barrel length (peaking around 14 inches), likely because of the induced drag of the fast rifling. If their claim that rotational energy significantly impacts lethality is true, then it's simply leaving money on the table if your round doesn't also doesn't become slow as hell after a 16" barrel (or whatever length you consider to be most practical).
Personally, that leads me to the conclusion that even if their claim about rotational energy translating to bigger temporary wound cavities and whatnot is wrong (which it may be), it seems pretty undeniable that higher rotational speed means the large blender-like petals of solid copper projectiles can carve more flesh or bone per square inch traveled. I would like to see how they perform with a cavitation based round like underwood offers and compare, see if there's any difference at all when it's fired from a fast twist barrel vs a slower twisted one.
It feels like a marginal gain, but a gain nonetheless.
>it seems pretty undeniable that higher rotational speed means the large blender-like petals of solid copper projectiles can carve more flesh or bone per square inch traveled.
This is prehistoric bullshit called the buzzsaw effect repackaged for modern morons.
If you’re confined to a subsonic projectile the only way you can make the round more lethal is to increase the mass of the bullet, spin it faster, and get the round to contact more tissue by designing the bullet to expand but stay together.
I’d really like to see the 1 in 1 gel tests they say they have.
man, if only there was a material more dense than copper we could make a bullet out of, or in part out of, which would raise its mass, and therefore it's muzzle energy at a given velocity.
damn, if only I knew anything about bullet construction.
>So the the mass is limited by what the desired expansion characteristics are.
man, if only things could be made out of material
[...]
458 has more energy at all ranges
all the other 3 fit in an AR-15
bigger package, less performance, whoa.
[...] >5 factors, >lists 4 >one of which have never, in the history of ballistics, been shown to increase any terminal performance in any way >one of which is the same for all subsonic cartridges.
holy smokes, is this the best you can do? go ahead, get back to me with how much muzzle energy you gain going from 1:9 to 1:3 twist for a 300 gr bullet at 1050fps. I've done the math, but it's important to establish repeatability, and who knows, maybe I screwed up.
>one of which have never, in the history of ballistics, been shown to increase any terminal performance in any way
I don't believe any studies have been done specifically on solid copper projectiles that expand as the ones we have now do. If there isn't a large gap between the petals, rather a more uniform expansion as seen on traditional hollowpoints, then it would make sense if no additional damage is found.
If there are such studies, I'd love to see them. However, all visual evidence I've seen from gel tests seem to indicate that the idea of a buzzsaw effect does have implications for wide expanding projectiles specifically. You can argue about the use of such projectiles and their validity compared to more uniform hollowpoints, but that's another argument entirely. I am skeptical about their claims on if it improves anything but that, but that alone has significant implications for subsonic rounds, which is why I suggested using lehigh bullets or something else to isolate for factors relating to metal geometry.
To me, the interesting aspect of having such a short spin is minimizing barrel length. So you have 1 in 3 twist? why not make a rifle barrel that is there or four inches long? With extra hot hybrid case ammo?
short spin = fast spin* whoops. The idea being you could get all the stabilization in a very short barrel and coupled with extremely high pressure hot rounds, you could have rifle perfomance in a very short package
Why do you think the number of turns the bullet makes inside the barrel has anything to do with how stabilized the bullet is once it leaves the barrel?
I would think the bullet needs to achieve a certain angular velocity to have stabilization
4 months ago
Anonymous
This is determined by twist rate and velocity, at no point does "number of rotations the bullet makes in the barrel" come into the physics.
4 months ago
Anonymous
how do you think it gets spun at the correct speed you fricking idiot
4 months ago
Anonymous
Here ya go anon, here's the formula for bullet stability. Show me exactly which term in the equation is "number of times the bullet spins in the barrel before exiting".
4 months ago
Anonymous
And here's another variant on it. Again, please show me exactly which term in the equation is "number of times the bullet spins in the barrel before exiting".
4 months ago
Anonymous
so according to this gyroscopic stability increases with the square of the twist rate so a faster twist rate would increase gyroscopic stability quickly
4 months ago
Anonymous
That's not the point under discussion. See
To me, the interesting aspect of having such a short spin is minimizing barrel length. So you have 1 in 3 twist? why not make a rifle barrel that is there or four inches long? With extra hot hybrid case ammo?
- the topic is the number of rotations the bullet must make in the barrel before it is actually stabilized. And the answer, as inspection of the stability equations quickly reveals, is utterly immaterial. Also, as a demonstration of this, snub nosed revolvers have no problems stabilizing their bullets despite having only an inch or so of barrel length and a twist rate of 1:16 - meaning the bullet only makes about 1/10th of a turn before leaving the barrel.
4 months ago
Anonymous
>a faster twist rate would increase gyroscopic stability quickly >quickly
Take another look at the equations and tell me where "quickly" (e.g. time in barrel) factors in to them.
4 months ago
Anonymous
do you actually expect any ballistic literacy from these people?
4 months ago
Anonymous
Not really, I just enjoy mocking the high school dropouts.
4 months ago
Anonymous
I’m not too well versed in physics, but shouldn’t center of pressure and center of mass and their relationship to eachother be included in there somewhere? Or is that what gyroscopic stability factor is?
4 months ago
Anonymous
>is that what gyroscopic stability factor is?
Yep. It's something that can be either measured instrumentally or worked out with discrete calculus and an accurate specification for the bullet. If you're willing to get "good enough" then you can just use some generic stability factor for e.g. "jacketed lead core spitzer rifle bullet" or "hollow point pistol bullet" - that's what most of the twist rate calculators are doing.
4 months ago
Anonymous
That’s a function of twist rate and muzzle velocity, not barrel length (or number of twists contained within the barrel)
As long as the rifling twist rate is fast enough to stabilize the bullet at the muzzle velocity, it doesn't matter if the bullet makes 1, 2, or 20 turns inside the barrel. Look at a snub nose revolver, the bullet makes something like 1/10th of a revolution between the time it hits the forcing cone and the time its ass leaves the barrel. Stabilizes just fine.
NTA, twist rate has nothing to do with barrel length. The spin is imparted instantly upon engraving and will always come out of the barrel spinning once every 3 inches. Even if the barrel were only an inch long.
>whether or not the added spin speed actually helps terminal performance as they claim
Came across it developing 300 blk (wanted more than 1:5, but that was the threshold for stabilizing both subs & supers). Permanent wound cavity comparisons are out there for review. It's doing with subs what I'd otherwise like 35 Whelan for, and even more with supers. Aids stabilization of the subs, farther as well.
If you compare pictures of Maker Rex expanding bullets in 8.6 and other calibers, you’ll see the 1:3 twist rate has the effect of turning the petals 90 degrees along their axis, presenting a cutting edge in the direction of travel, and resisting folding back onto the shank. Net result is wider expansion AND higher SD while expanded. That’s pretty sick. Plus the bullet’s so stable it doesn’t tumble. In gel footage you can see the petals tracing (cutting) a helix throughout the entire length of the block. What I REALLY want to see is this idea taken to the extreme with ultra heavy .224 bullets. Like 120gr +, L:D of 7+, 1:2 twist, and with maximum expansion/terminal effect for minimal powder charge. Also would suppress much better than either of the blackouts. Can use a straight wall case like the 5.56 Knox. 100rd quad stacks the size of a regular PMAG.
Anywho. To answer OPs question, I like spitzer thumpers, so I like 8.6 blackout. Besides that, A hybrid case ~100gr with low form factor would make a pretty cool neo-CETME round too. Doubt any bullet would hold up to 1:3 twist at ~3000fps though. Maybe with a slower twist.
It’s legit but ammo is scarce and hand reloading by way of case conversion can create case wall thickness problems. They wisely made the system so it could use existing pmags.
I’m planning to build a short semiauto for an HD gun. Supposed to be very quiet. If you’ve never shot a gun in a small room, you can’t believe how loud it is.
[...]
Frick off paid contractor homosexual. This thread is what k is really for. Get your gay israeli brown aliens to die spreading man on man anal around the world.
I was here when your two gay fathers were still scheming to adopt you.
man, if only there was a material more dense than copper we could make a bullet out of, or in part out of, which would raise its mass, and therefore it's muzzle energy at a given velocity.
damn, if only I knew anything about bullet construction.
You understand mass and velocity but construction and material type impacts lethality. If the round was depleted uranium it would have great penetration but wouldn’t expand. If it were lead it would have more mass but would break apart due to the rotational rate. So the the mass is limited by what the desired expansion characteristics are.
>So the the mass is limited by what the desired expansion characteristics are.
man, if only things could be made out of material
Nothing on that chart outperforms 8.6
458 has more energy at all ranges
all the other 3 fit in an AR-15
bigger package, less performance, whoa.
It’s the total package guy. 5 factors,
Velocity
Rotation rate
Bullet design
Material
Also, a weapon is a total system. 8.6 it can feed reliably from a pmag instead of some off brand unreliable mag.
>5 factors, >lists 4 >one of which have never, in the history of ballistics, been shown to increase any terminal performance in any way >one of which is the same for all subsonic cartridges.
holy smokes, is this the best you can do? go ahead, get back to me with how much muzzle energy you gain going from 1:9 to 1:3 twist for a 300 gr bullet at 1050fps. I've done the math, but it's important to establish repeatability, and who knows, maybe I screwed up.
moron sperg, 458 has terrible magazine capacity and was therefore replaced with 300blk.
Again, since you can’t figure this out, the whole point was to make a more lethal subsonic round.
Since the limitation was subsonic speed, they had to increase the size of the bullet. The only place they could speed up the round was with rotation. They specifically constructed the bullet so it would expand but not break apart. It’s like getting shot with a crossbow bolt. They selected a round that would fit into an ar10 mag and run reliably. This combination makes the overall system lethal. It’s also quiet and performs well from a short barrel.
The 350 can’t load into a pmag. The 300 is less lethal and getting a twist faster than 1 in 5 takes a custom barrel.
Nothing on that chart outperforms 8.6
I’m referring to expanding bullets. The sig rattler was limited to 1 in 5 so expanding bullets wouldn’t break apart. The 8.6 uses copper slugs to keep the bullets from breaking apart.
>The only place they could speed up the round was with rotation.
so, how much energy did they gain with this miraculous optimization and is it more than is possible with a jacketed bullet construction?
it's weird how nobody wants to answer this very simple physics question. >Again, since you can’t figure this out, the whole point was to make a more lethal subsonic round.
man, if only there was a round that weighed nearly twice as much, like 458 Socom.
.458 SOCOM, .450 Bushmaster, and .50 Beowulf are the general category of "big bore" for the AR-15 platform. .300 BLK doesn't "replace" any of them, even if you're referring to strictly subsonic loads. The only recent cartridge that could "replace" any of them is the .400 Legend. Which would also be better than the 8.6 BLK at being "fat and slow" simply by virtue of fitting in an AR-15. >VGH THE TWIST RATE BUZZSAW THO
ok opinion discarded have a nice day
4 months ago
Anonymous
Not just that, but the 400 legend mogs the aforementioned AR15 thumpers by virtue of its being able to double stack. The others are moronic single or ~1.5 stack
>458 has more energy at all ranges
You've never killed anything have you?
Energy is a wive's tale. Energy doesn't kill anything, punching hole in vital organs does. This is ensured by:
1) Shot placement
2) Projectile integrity
3) Velocity at impact
8.6 drifts less and drops less than 458, which aids shot placement.
There are numerous 338 bullets that will zip through anything you might want to shoot them into without zooking up.
As you can see in the charts, 8.6 arrives on target with higher velocity than 458 at all ranges.
>Velocity at impact
is an old wives tale. >You've never killed anything have you?
I'm sure you've run rigorously controlled scientific studies on terminal ballistics. but that doesn't surprise me, because neither has Q.
this Black person did and velocity has nothing to do with it except as a component of momentum.
also, if velocity and drop are so important, why not use a supersonic round, like .308? it has far better ballistics than subsonic .338 whisper. >8.6 drifts less and drops less
how much? go ahead and say the numbers, because when I get a chance I'm going to measure the subsonic BC of those 576gr bullets and recompute the ballistics tables.
just to prove a point, what do you think the BC of pic related is at 1000FPS? I measured it with my lab radar.
moron sperg, 458 has terrible magazine capacity and was therefore replaced with 300blk.
Again, since you can’t figure this out, the whole point was to make a more lethal subsonic round.
Since the limitation was subsonic speed, they had to increase the size of the bullet. The only place they could speed up the round was with rotation. They specifically constructed the bullet so it would expand but not break apart. It’s like getting shot with a crossbow bolt. They selected a round that would fit into an ar10 mag and run reliably. This combination makes the overall system lethal. It’s also quiet and performs well from a short barrel.
The 350 can’t load into a pmag. The 300 is less lethal and getting a twist faster than 1 in 5 takes a custom barrel.
[...]
I’m referring to expanding bullets. The sig rattler was limited to 1 in 5 so expanding bullets wouldn’t break apart. The 8.6 uses copper slugs to keep the bullets from breaking apart.
>rotational energy
how much energy do you think 8.6 gains from going from a 1:9 to 1:3 twist rate at 1050fps. it's simple math, you just have to have heard of a second moment of inertia before.
The fuddlore about twist rates and buzzsawing has been around for a very long time. This is from a 1973 Sports Afield article and I've seen even older gun rags talking about the same nonsense. It's practically the same script 8.6 Blackout shills follow today, right down to shitting on the guy who tells him physics don't work that way.
458 socom is a moronic cartridge that has no justification for its existence. MUH ENERGY! Look how much of its starting energy it has lost by 500 yards. Look how much more drop it has. Look at that piss poor BC. The recoil is far too great for what it is, and mags hold like 7. Compare that to the 8.6’s flat energy curve, 25rd mags, and half the recoil.
>starting energy it has lost by 500 yards
are you being moronic on purpose? you better not be. >energy curve
we've got a new ballistics term that nobody has ever discussed before. >half the recoil
and half the energy. there is no free lunch in physics, my dude.
458 mogs .338 whisper.
oh, I mean whatever that gaylord renamed and took credit for this time.
If you compare pictures of Maker Rex expanding bullets in 8.6 and other calibers, you’ll see the 1:3 twist rate has the effect of turning the petals 90 degrees along their axis, presenting a cutting edge in the direction of travel, and resisting folding back onto the shank. Net result is wider expansion AND higher SD while expanded. That’s pretty sick. Plus the bullet’s so stable it doesn’t tumble. In gel footage you can see the petals tracing (cutting) a helix throughout the entire length of the block. What I REALLY want to see is this idea taken to the extreme with ultra heavy .224 bullets. Like 120gr +, L:D of 7+, 1:2 twist, and with maximum expansion/terminal effect for minimal powder charge. Also would suppress much better than either of the blackouts. Can use a straight wall case like the 5.56 Knox. 100rd quad stacks the size of a regular PMAG.
Anywho. To answer OPs question, I like spitzer thumpers, so I like 8.6 blackout. Besides that, A hybrid case ~100gr with low form factor would make a pretty cool neo-CETME round too. Doubt any bullet would hold up to 1:3 twist at ~3000fps though. Maybe with a slower twist.
>petals tracing (cutting) a helix throughout the entire length of the block.
which is exactly what every hollow point does, but this times it's a sales pitch so it matters more >Maybe with a slower twist.
man, that's crazy. what if we just used normal twist rates and bullet construction to achieve higher muzzle energies?
Still waiting for someone to tell me how much energy a 300gr solid brass bullet gains at 1050fps going from 1:9 to 1:3 twist.
> which is exactly what every hollow point does, but this times it's a sales pitch so it matters more
No, moron. My point is the bullet stays oriented in its direction of travel. The proof is the traced helix.. Regular hollow points do not do that.
> man, that's crazy. what if we just used normal twist rates and bullet construction to achieve higher muzzle energies?
No the 1 in 3 twist is good for <2000fps, was just thinking of what else the 8.6 could be given a low overbore ratio and super long ogive. Really all that’s standing in the way of a new CETME round is its twist rate. Superheavy subs, mid weight mid velocity whatever load, and ultralight intermediate cartridge. It could be 3 cartridges in 1
Pretty sure the extra energy from 1:9 to 1:3 is negligible, I think someone here did the math a while back and came up with like single digit ft*lbs. but that’s not the point (and the “rotational energy” thing is indeed a marketing gimmick).. I outlined the benefit of the fast twist in my post you quoted. Read it again.
I used to be like you, thinking energy is everything. You’ll grow out of it
> >energy curve
we've got a new ballistics term that nobody has ever discussed before. >half the recoil
and half the energy. there is no free lunch in physics, my dude.
This is hilarious, because the term I used that you laughed at IS the free lunch. If both cartridges are getting equal energy at 500 yards, the one that starts off with less energy will have less recoil, a smaller case, higher capacity, etc without degrading its terminal performance at 500yds.
>500yds
dear moron
nobody does anything but target shooting with subsonics at 500 yards.
warm regards,
reality.
> which is exactly what every hollow point does, but this times it's a sales pitch so it matters more
No, moron. My point is the bullet stays oriented in its direction of travel. The proof is the traced helix.. Regular hollow points do not do that.
> man, that's crazy. what if we just used normal twist rates and bullet construction to achieve higher muzzle energies?
No the 1 in 3 twist is good for <2000fps, was just thinking of what else the 8.6 could be given a low overbore ratio and super long ogive. Really all that’s standing in the way of a new CETME round is its twist rate. Superheavy subs, mid weight mid velocity whatever load, and ultralight intermediate cartridge. It could be 3 cartridges in 1
Pretty sure the extra energy from 1:9 to 1:3 is negligible, I think someone here did the math a while back and came up with like single digit ft*lbs. but that’s not the point (and the “rotational energy” thing is indeed a marketing gimmick).. I outlined the benefit of the fast twist in my post you quoted. Read it again.
I used to be like you, thinking energy is everything. You’ll grow out of it
>An expert witness testified Jan. 24 that the murder weapon was a .300 Blackout semiautomatic rifle that had been used before at the Murdaughs’ spacious hunting estate in Colleton County. Ballistic tests showed shell casings found near Maggie’s body had been ejected from the same gun as older casings recovered elsewhere on the property, he said.
I don't doubt he was significantly involved/caused their murder/deaths, but I still don't see how he got it all done in the time allotted. if I remember right they never found the AR that he wasted his wife with, but I don't know how he disappeared it or did the whole >wife's phone half a mile away thing.
I find it nearly impossible that other people weren't involved but they stopped looking and were like >nope we got everyone.
which I just don't see.
America tries to make 9x39
Except that doesn't make any sense, because 9x39 is scaled up 762x39, and 762x39 is/was the Russian equivalent of 556, and that position already belong to 300 BLK
Except that doesn't make any sense, because 545 is the Russian response to 556, so that would be the Russian equivalent to 556 and 762x39 would be .300 blk equiv and that makes sense because they have similar performance and this means 8.6 is the American 9x39
Except that doesn't make any sense, because 8.6 doesn't seem to be in an AR platform in OP's pic like the 300 and 556, which means it doesn't follow the AK's pattern of 545 - 762 - 9 and the honor should probably go to .458 socom.
Except that doesn't make any sense, because .458 doesn't match 9x39's purpose which brings us right back to 300 blk for short-range subsonic sentry slaying
Except that doesn't make any s- >head explodes
>because 9x39 is scaled up 762x39 >762x39 is/was the Russian equivalent of 556
Please refrain from posting if you have no knowledge about the topic you're talking about
A flop on all levels
Firstly, the name doesn't make sense. It should be 330 Blackout
Secondly, the cartridge doesn't make sense. 338 Spectre does everything this stupid cartridge can but in a smaller package. With 22 nosler/350 legend as a parent case you don't even need a new bolt anymore. Maybe PSA will do that and trademark the 330 aac blackout name kek
Thirdly, short action cartridges can shoot a lot more mass and have subsonic cartridges that don't get mogged by 45 acp. Rotational energy goes up by the square of bore diameter and linearly with mass if you wanna do meme bullets. 408, 458, or 510 to name a few would mog this failure of a cartridge.
For me? It's the 50 American Eagle, the best subsonic short action round
It's literally just a copy of 9x39. What's so special about it and why bother making a whole new caliper instead of just using 9x39?? In fact 9x39 is very slightly better because of the bigger caliber.
When it comes to hunting, which is what 8.6 is marketed for as far as I've seen, shot placement is all that matters. Half moronic Alaskan Inuits kill bull Moose with .223 regularly. Half moronic West Virginians kill white tail does with 12g slugs regularly
So if suppressing your hunting rifle matters to you then yeah, 8.6 is legit. But don't act like the flashy massively exoanding high-twist rate projectile is ever going to compensate for shot placement
Every rifle round invented after .308 is a meme but as long as it can kill criminals then its a good cartridge in my opinion.
8.6 blk might have been more popular if it fit in an AR-15 action rather than an AR-10 action. We were so close to a western version of 9x39mm, but Q would rather have another deer killing round that will get ignored once hunters realize that their 30-06, .308, and 30-30 have had no problem killing deer at all.
Agreed. But 338 spectre is a wildcat that nobody sells. I have an LWRC receiver spec 6.8 SPC that I put together before I realized 6.8 SPC is a meme. I Wish there was literally any sensible alternative to chamber it in. I’d love a 338 spectre, but I’m not gonna load ammo for it.
Why can't 8.6 shills just come right out and say how much rotational energy the meme twist adds? It must be a massive number based on their claims. Surely it isn't just marketing BS
Question that really matters: is a singular mentally-ill homosexual/paid shill that starts a GT thread nearly every day or are we dealing with an /mlp/ situation where it's a gaggle of insufferable homosexuals/his current fanbase of 12-year olds? At leaat with the /mlp/ we got plot and horse pussy.
yeah
Depends if the ARMY is really serious about moving back to a battle rifle then yea it might become the real thing
I recognize that this is a slide thread because of the GT thumbnail and low effort OP question, but regardless I think it's effective. The main controversy is whether or not the added spin speed actually helps terminal performance as they claim. They did some shady stuff with gel tests to make their round look a bit flashier for the camera -- stuff like water splashed on the block, so some people dismiss it, but having seen other gel tests I'm quite impressed at how well the cavity follows the spin of the round. Additionally, I've seen barrel length tests that show that speed drops off very quickly with barrel length (peaking around 14 inches), likely because of the induced drag of the fast rifling. If their claim that rotational energy significantly impacts lethality is true, then it's simply leaving money on the table if your round doesn't also doesn't become slow as hell after a 16" barrel (or whatever length you consider to be most practical).
Personally, that leads me to the conclusion that even if their claim about rotational energy translating to bigger temporary wound cavities and whatnot is wrong (which it may be), it seems pretty undeniable that higher rotational speed means the large blender-like petals of solid copper projectiles can carve more flesh or bone per square inch traveled. I would like to see how they perform with a cavitation based round like underwood offers and compare, see if there's any difference at all when it's fired from a fast twist barrel vs a slower twisted one.
It feels like a marginal gain, but a gain nonetheless.
>it seems pretty undeniable that higher rotational speed means the large blender-like petals of solid copper projectiles can carve more flesh or bone per square inch traveled.
This is prehistoric bullshit called the buzzsaw effect repackaged for modern morons.
If you’re confined to a subsonic projectile the only way you can make the round more lethal is to increase the mass of the bullet, spin it faster, and get the round to contact more tissue by designing the bullet to expand but stay together.
I’d really like to see the 1 in 1 gel tests they say they have.
.
man, if only there was a material more dense than copper we could make a bullet out of, or in part out of, which would raise its mass, and therefore it's muzzle energy at a given velocity.
damn, if only I knew anything about bullet construction.
I’m doubting 1 in 1. The engraving angle would be greater than 45 degrees.
>one of which have never, in the history of ballistics, been shown to increase any terminal performance in any way
I don't believe any studies have been done specifically on solid copper projectiles that expand as the ones we have now do. If there isn't a large gap between the petals, rather a more uniform expansion as seen on traditional hollowpoints, then it would make sense if no additional damage is found.
If there are such studies, I'd love to see them. However, all visual evidence I've seen from gel tests seem to indicate that the idea of a buzzsaw effect does have implications for wide expanding projectiles specifically. You can argue about the use of such projectiles and their validity compared to more uniform hollowpoints, but that's another argument entirely. I am skeptical about their claims on if it improves anything but that, but that alone has significant implications for subsonic rounds, which is why I suggested using lehigh bullets or something else to isolate for factors relating to metal geometry.
To me, the interesting aspect of having such a short spin is minimizing barrel length. So you have 1 in 3 twist? why not make a rifle barrel that is there or four inches long? With extra hot hybrid case ammo?
short spin = fast spin* whoops. The idea being you could get all the stabilization in a very short barrel and coupled with extremely high pressure hot rounds, you could have rifle perfomance in a very short package
Why do you think the number of turns the bullet makes inside the barrel has anything to do with how stabilized the bullet is once it leaves the barrel?
Do you think the barrel has to be long enough for the bullet to make a full rotation in its length to be stabilized?
I would think the bullet needs to achieve a certain angular velocity to have stabilization
This is determined by twist rate and velocity, at no point does "number of rotations the bullet makes in the barrel" come into the physics.
how do you think it gets spun at the correct speed you fricking idiot
Here ya go anon, here's the formula for bullet stability. Show me exactly which term in the equation is "number of times the bullet spins in the barrel before exiting".
And here's another variant on it. Again, please show me exactly which term in the equation is "number of times the bullet spins in the barrel before exiting".
so according to this gyroscopic stability increases with the square of the twist rate so a faster twist rate would increase gyroscopic stability quickly
That's not the point under discussion. See
- the topic is the number of rotations the bullet must make in the barrel before it is actually stabilized. And the answer, as inspection of the stability equations quickly reveals, is utterly immaterial. Also, as a demonstration of this, snub nosed revolvers have no problems stabilizing their bullets despite having only an inch or so of barrel length and a twist rate of 1:16 - meaning the bullet only makes about 1/10th of a turn before leaving the barrel.
>a faster twist rate would increase gyroscopic stability quickly
>quickly
Take another look at the equations and tell me where "quickly" (e.g. time in barrel) factors in to them.
do you actually expect any ballistic literacy from these people?
Not really, I just enjoy mocking the high school dropouts.
I’m not too well versed in physics, but shouldn’t center of pressure and center of mass and their relationship to eachother be included in there somewhere? Or is that what gyroscopic stability factor is?
>is that what gyroscopic stability factor is?
Yep. It's something that can be either measured instrumentally or worked out with discrete calculus and an accurate specification for the bullet. If you're willing to get "good enough" then you can just use some generic stability factor for e.g. "jacketed lead core spitzer rifle bullet" or "hollow point pistol bullet" - that's what most of the twist rate calculators are doing.
That’s a function of twist rate and muzzle velocity, not barrel length (or number of twists contained within the barrel)
So, by your logic, I could just use a smoothbore barrel and it would have identical performance?
one of the most moronic things I have read today
.....wat?
As long as the rifling twist rate is fast enough to stabilize the bullet at the muzzle velocity, it doesn't matter if the bullet makes 1, 2, or 20 turns inside the barrel. Look at a snub nose revolver, the bullet makes something like 1/10th of a revolution between the time it hits the forcing cone and the time its ass leaves the barrel. Stabilizes just fine.
mien negger wat
NTA, twist rate has nothing to do with barrel length. The spin is imparted instantly upon engraving and will always come out of the barrel spinning once every 3 inches. Even if the barrel were only an inch long.
>whether or not the added spin speed actually helps terminal performance as they claim
Came across it developing 300 blk (wanted more than 1:5, but that was the threshold for stabilizing both subs & supers). Permanent wound cavity comparisons are out there for review. It's doing with subs what I'd otherwise like 35 Whelan for, and even more with supers. Aids stabilization of the subs, farther as well.
If you compare pictures of Maker Rex expanding bullets in 8.6 and other calibers, you’ll see the 1:3 twist rate has the effect of turning the petals 90 degrees along their axis, presenting a cutting edge in the direction of travel, and resisting folding back onto the shank. Net result is wider expansion AND higher SD while expanded. That’s pretty sick. Plus the bullet’s so stable it doesn’t tumble. In gel footage you can see the petals tracing (cutting) a helix throughout the entire length of the block. What I REALLY want to see is this idea taken to the extreme with ultra heavy .224 bullets. Like 120gr +, L:D of 7+, 1:2 twist, and with maximum expansion/terminal effect for minimal powder charge. Also would suppress much better than either of the blackouts. Can use a straight wall case like the 5.56 Knox. 100rd quad stacks the size of a regular PMAG.
Anywho. To answer OPs question, I like spitzer thumpers, so I like 8.6 blackout. Besides that, A hybrid case ~100gr with low form factor would make a pretty cool neo-CETME round too. Doubt any bullet would hold up to 1:3 twist at ~3000fps though. Maybe with a slower twist.
It’s legit but ammo is scarce and hand reloading by way of case conversion can create case wall thickness problems. They wisely made the system so it could use existing pmags.
I’m planning to build a short semiauto for an HD gun. Supposed to be very quiet. If you’ve never shot a gun in a small room, you can’t believe how loud it is.
Frick off paid contractor homosexual. This thread is what k is really for. Get your gay israeli brown aliens to die spreading man on man anal around the world.
>k
lurk moar newhomosexual
I was here when your two gay fathers were still scheming to adopt you.
You understand mass and velocity but construction and material type impacts lethality. If the round was depleted uranium it would have great penetration but wouldn’t expand. If it were lead it would have more mass but would break apart due to the rotational rate. So the the mass is limited by what the desired expansion characteristics are.
>So the the mass is limited by what the desired expansion characteristics are.
man, if only things could be made out of material
458 has more energy at all ranges
all the other 3 fit in an AR-15
bigger package, less performance, whoa.
>5 factors,
>lists 4
>one of which have never, in the history of ballistics, been shown to increase any terminal performance in any way
>one of which is the same for all subsonic cartridges.
holy smokes, is this the best you can do? go ahead, get back to me with how much muzzle energy you gain going from 1:9 to 1:3 twist for a 300 gr bullet at 1050fps. I've done the math, but it's important to establish repeatability, and who knows, maybe I screwed up.
moron sperg, 458 has terrible magazine capacity and was therefore replaced with 300blk.
Again, since you can’t figure this out, the whole point was to make a more lethal subsonic round.
Since the limitation was subsonic speed, they had to increase the size of the bullet. The only place they could speed up the round was with rotation. They specifically constructed the bullet so it would expand but not break apart. It’s like getting shot with a crossbow bolt. They selected a round that would fit into an ar10 mag and run reliably. This combination makes the overall system lethal. It’s also quiet and performs well from a short barrel.
The 350 can’t load into a pmag. The 300 is less lethal and getting a twist faster than 1 in 5 takes a custom barrel.
I’m referring to expanding bullets. The sig rattler was limited to 1 in 5 so expanding bullets wouldn’t break apart. The 8.6 uses copper slugs to keep the bullets from breaking apart.
>The only place they could speed up the round was with rotation.
so, how much energy did they gain with this miraculous optimization and is it more than is possible with a jacketed bullet construction?
it's weird how nobody wants to answer this very simple physics question.
>Again, since you can’t figure this out, the whole point was to make a more lethal subsonic round.
man, if only there was a round that weighed nearly twice as much, like 458 Socom.
>replaced with 300blk
brain broblems :DDDDD
.458 SOCOM, .450 Bushmaster, and .50 Beowulf are the general category of "big bore" for the AR-15 platform. .300 BLK doesn't "replace" any of them, even if you're referring to strictly subsonic loads. The only recent cartridge that could "replace" any of them is the .400 Legend. Which would also be better than the 8.6 BLK at being "fat and slow" simply by virtue of fitting in an AR-15.
>VGH THE TWIST RATE BUZZSAW THO
ok opinion discarded have a nice day
Not just that, but the 400 legend mogs the aforementioned AR15 thumpers by virtue of its being able to double stack. The others are moronic single or ~1.5 stack
>The 8.6 uses copper slugs to keep the bullets from breaking apart.
Bonded cup & core do fine in 1:3" 8.6 BLK.
>458 has more energy at all ranges
You've never killed anything have you?
Energy is a wive's tale. Energy doesn't kill anything, punching hole in vital organs does. This is ensured by:
1) Shot placement
2) Projectile integrity
3) Velocity at impact
8.6 drifts less and drops less than 458, which aids shot placement.
There are numerous 338 bullets that will zip through anything you might want to shoot them into without zooking up.
As you can see in the charts, 8.6 arrives on target with higher velocity than 458 at all ranges.
>Velocity at impact
is an old wives tale.
>You've never killed anything have you?
I'm sure you've run rigorously controlled scientific studies on terminal ballistics. but that doesn't surprise me, because neither has Q.
this Black person did and velocity has nothing to do with it except as a component of momentum.
also, if velocity and drop are so important, why not use a supersonic round, like .308? it has far better ballistics than subsonic .338 whisper.
>8.6 drifts less and drops less
how much? go ahead and say the numbers, because when I get a chance I'm going to measure the subsonic BC of those 576gr bullets and recompute the ballistics tables.
just to prove a point, what do you think the BC of pic related is at 1000FPS? I measured it with my lab radar.
>but would break apart due to the rotational rate
No it wouldn't you moron
>
Can't be any more expensive than literally any similar round
meme for technically illiterate hypebeasts to lap up.
out performed by other cartridges in smaller packages already.
These charts don’t account for rotational energy and only the 8.6 and 300blk can feed from a pmag.
>rotational energy
how much energy do you think 8.6 gains from going from a 1:9 to 1:3 twist rate at 1050fps. it's simple math, you just have to have heard of a second moment of inertia before.
It’s the total package guy. 5 factors,
Velocity
Rotation rate
Bullet design
Material
Also, a weapon is a total system. 8.6 it can feed reliably from a pmag instead of some off brand unreliable mag.
The fuddlore about twist rates and buzzsawing has been around for a very long time. This is from a 1973 Sports Afield article and I've seen even older gun rags talking about the same nonsense. It's practically the same script 8.6 Blackout shills follow today, right down to shitting on the guy who tells him physics don't work that way.
Nothing on that chart outperforms 8.6
Sorry, meant to quote. I’m on my phone.
458 socom is a moronic cartridge that has no justification for its existence. MUH ENERGY! Look how much of its starting energy it has lost by 500 yards. Look how much more drop it has. Look at that piss poor BC. The recoil is far too great for what it is, and mags hold like 7. Compare that to the 8.6’s flat energy curve, 25rd mags, and half the recoil.
>starting energy it has lost by 500 yards
are you being moronic on purpose? you better not be.
>energy curve
we've got a new ballistics term that nobody has ever discussed before.
>half the recoil
and half the energy. there is no free lunch in physics, my dude.
458 mogs .338 whisper.
oh, I mean whatever that gaylord renamed and took credit for this time.
>petals tracing (cutting) a helix throughout the entire length of the block.
which is exactly what every hollow point does, but this times it's a sales pitch so it matters more
>Maybe with a slower twist.
man, that's crazy. what if we just used normal twist rates and bullet construction to achieve higher muzzle energies?
Still waiting for someone to tell me how much energy a 300gr solid brass bullet gains at 1050fps going from 1:9 to 1:3 twist.
> which is exactly what every hollow point does, but this times it's a sales pitch so it matters more
No, moron. My point is the bullet stays oriented in its direction of travel. The proof is the traced helix.. Regular hollow points do not do that.
> man, that's crazy. what if we just used normal twist rates and bullet construction to achieve higher muzzle energies?
No the 1 in 3 twist is good for <2000fps, was just thinking of what else the 8.6 could be given a low overbore ratio and super long ogive. Really all that’s standing in the way of a new CETME round is its twist rate. Superheavy subs, mid weight mid velocity whatever load, and ultralight intermediate cartridge. It could be 3 cartridges in 1
Pretty sure the extra energy from 1:9 to 1:3 is negligible, I think someone here did the math a while back and came up with like single digit ft*lbs. but that’s not the point (and the “rotational energy” thing is indeed a marketing gimmick).. I outlined the benefit of the fast twist in my post you quoted. Read it again.
I used to be like you, thinking energy is everything. You’ll grow out of it
> >energy curve
we've got a new ballistics term that nobody has ever discussed before.
>half the recoil
and half the energy. there is no free lunch in physics, my dude.
This is hilarious, because the term I used that you laughed at IS the free lunch. If both cartridges are getting equal energy at 500 yards, the one that starts off with less energy will have less recoil, a smaller case, higher capacity, etc without degrading its terminal performance at 500yds.
>500yds
dear moron
nobody does anything but target shooting with subsonics at 500 yards.
warm regards,
reality.
>new CETME
oh, you are that moron.
Then why the frick are you posting ballistics charts out to 500 yards?
to make a point about how miniscule the impact is of BC on subsonic bullets, but since you didn't know that it was lost on you.
I genuinely can't tell if this is ironic or an actual nu-/k/ nafohomosexual post
I hope garandthumb dies soon
I for one think its based to call out nu/k/ redditors like you.
Alex Murdaugh is a big fan
[citation needed]
He killed his wife and son with 8.6mm Blackout
>An expert witness testified Jan. 24 that the murder weapon was a .300 Blackout semiautomatic rifle that had been used before at the Murdaughs’ spacious hunting estate in Colleton County. Ballistic tests showed shell casings found near Maggie’s body had been ejected from the same gun as older casings recovered elsewhere on the property, he said.
>Is actually named Murder
>Kills his whole family
Get the frick outta here
I don't doubt he was significantly involved/caused their murder/deaths, but I still don't see how he got it all done in the time allotted. if I remember right they never found the AR that he wasted his wife with, but I don't know how he disappeared it or did the whole
>wife's phone half a mile away thing.
I find it nearly impossible that other people weren't involved but they stopped looking and were like
>nope we got everyone.
which I just don't see.
Cops prefer speedy cases. Which is why they rule suspicious deaths suicides.
America tries to make 9x39
Except that doesn't make any sense, because 9x39 is scaled up 762x39, and 762x39 is/was the Russian equivalent of 556, and that position already belong to 300 BLK
Except that doesn't make any sense, because 545 is the Russian response to 556, so that would be the Russian equivalent to 556 and 762x39 would be .300 blk equiv and that makes sense because they have similar performance and this means 8.6 is the American 9x39
Except that doesn't make any sense, because 8.6 doesn't seem to be in an AR platform in OP's pic like the 300 and 556, which means it doesn't follow the AK's pattern of 545 - 762 - 9 and the honor should probably go to .458 socom.
Except that doesn't make any sense, because .458 doesn't match 9x39's purpose which brings us right back to 300 blk for short-range subsonic sentry slaying
Except that doesn't make any s-
>head explodes
>because 9x39 is scaled up 762x39
>762x39 is/was the Russian equivalent of 556
Please refrain from posting if you have no knowledge about the topic you're talking about
Rest of the post is valid.
>5.56 is the American version of 7.62x39
There, I fixed it 4u, you happy?
Nta but
>5.56 is America's IMPROVED version of 7.62x39
Fixed it further for y'all
Got me there
>
>because 9x39 is scaled up 762x39
>implying it isn't
Your gayyyy
Nuh uh~
Nuh uh
A flop on all levels
Firstly, the name doesn't make sense. It should be 330 Blackout
Secondly, the cartridge doesn't make sense. 338 Spectre does everything this stupid cartridge can but in a smaller package. With 22 nosler/350 legend as a parent case you don't even need a new bolt anymore. Maybe PSA will do that and trademark the 330 aac blackout name kek
Thirdly, short action cartridges can shoot a lot more mass and have subsonic cartridges that don't get mogged by 45 acp. Rotational energy goes up by the square of bore diameter and linearly with mass if you wanna do meme bullets. 408, 458, or 510 to name a few would mog this failure of a cartridge.
For me? It's the 50 American Eagle, the best subsonic short action round
It's literally just a copy of 9x39. What's so special about it and why bother making a whole new caliper instead of just using 9x39?? In fact 9x39 is very slightly better because of the bigger caliber.
When it comes to hunting, which is what 8.6 is marketed for as far as I've seen, shot placement is all that matters. Half moronic Alaskan Inuits kill bull Moose with .223 regularly. Half moronic West Virginians kill white tail does with 12g slugs regularly
So if suppressing your hunting rifle matters to you then yeah, 8.6 is legit. But don't act like the flashy massively exoanding high-twist rate projectile is ever going to compensate for shot placement
Every rifle round invented after .308 is a meme but as long as it can kill criminals then its a good cartridge in my opinion.
8.6 blk might have been more popular if it fit in an AR-15 action rather than an AR-10 action. We were so close to a western version of 9x39mm, but Q would rather have another deer killing round that will get ignored once hunters realize that their 30-06, .308, and 30-30 have had no problem killing deer at all.
>western version of 9x39
We got two.. 300 blackout or 350 legend, take your pick.
also .338 Spectre if you hate the mainstream.
8.6 Blackout is just strictly inferior to existing solutions on the market
Agreed. But 338 spectre is a wildcat that nobody sells. I have an LWRC receiver spec 6.8 SPC that I put together before I realized 6.8 SPC is a meme. I Wish there was literally any sensible alternative to chamber it in. I’d love a 338 spectre, but I’m not gonna load ammo for it.
>.300 blackout
You're trolling, right?
>Q
Into the trash it goes
STOP SPAMMING THE FRICKING CATALOG FFS
man I would love a HK51 with a can for 8.6, for no other reason other than I think it'll be cool lol
That’s all the reason you need, anon.
It would def be cool
8.6 is made from .308 right? Would you need to do anything besides a barrel swap + tuning?
> 8.6 is made from .308 right?
Technically 6.5CM, but yeah.
Why can't 8.6 shills just come right out and say how much rotational energy the meme twist adds? It must be a massive number based on their claims. Surely it isn't just marketing BS
real meme
Still waiting for one of the 8.6 hypebeasts to do the math and tell me what the M M M MONSTER ENERGY GAIN it gets from a 1:3 twist is.
>Smaller potential bullet weight than .458 socom
>AR-10 platform
I don't get it
Question that really matters: is a singular mentally-ill homosexual/paid shill that starts a GT thread nearly every day or are we dealing with an /mlp/ situation where it's a gaggle of insufferable homosexuals/his current fanbase of 12-year olds? At leaat with the /mlp/ we got plot and horse pussy.