>poopaloo pops off >load up kit >prepare my 20" ar with collapsible stock >meet up with pals >see kevin with 2 backpacks >one for the kit and one to carry his multiple uppers with different barrel lengths to cover all applications >cant take him into any of those applications because he fumbles around and makes a shit ton of noise >ambushes and the element of surprise are gone when he's involved
A suppressor is a metal tube with chambers that capture gases from the escaping projectile. They aren't extra barrel length. They are more likely to slow the projectile than accelerate it.
Iirc in real world testing a suppressor will increase muzzle velocity but not by a significant amount, definitely not enough to make up the difference between between 14.5 and 20" and thus, the M16 prevails.
I never understood the 700-950 RPM. Is it referring to different barrel length fire rates, or is it actually completely randomized between those values?
No, because 24" barrels are mostly targeted to varminters who don't care about weight and do care about how fast their barrel warms up, but ADCO (or equivalent) will happily lathe your barrel down to whatever profile you want for a reasonable price.
Interesting take. I live in cornfield country, I made this thread cuz I’m thinking of upgrading my go to rifle from a 14.5 with a 1-6x LPVO to a 20” with a 1-8x. Ive already got everything ordered, can’t wait to see how it looks slapped together
Still close to velocity as 20in while more velocity then 16in. Still manuverable as a 16in, wtf are you talkin bout?? I was actually ordeing a 20in upper and a lower but guess what i sent it back and bought 18in upper last minute
That chart is way off. M193 out of a 20" is about 3180-3220, depending on the ammo. Out of a 16", you are getting about 3050 fps. It may not seem like much, but that extra 150 fps means the M193 from the 20" still has bullet upset to almost 200 yards, whereas the 16" only has bullet upset to about 125 yards. Not to mention a flatter trajectory to mid ranges, such as 250-400 yards. And because it's going faster at range, it's bucking the wind a bit better, too.
You're not getting a 150 fps difference between 20" and 16" At most it will be 120, and with most other loads it's actually closer to 100 fps difference. Basically indistinguishable.
2 years ago
Anonymous
with as fast as 5.56 decelerates every inch of barrel you cut substantially reduces its effective range, esp comparing to other rifle cartridges
2 years ago
Anonymous
1. So why 20" instead of 22", 24", &c.?
2. Looking at the procurement decisions made by LE/mil orgs that actually shoot people regularly, 14.5"–16" seems like it's good enough for most realistic use cases—do you disagree? If so, why?
2 years ago
Anonymous
because
most target load .223 you're shooting is probably around 3050 yes but m193's spec is literally 3250fps out of a 20" barrel
u fricking dummy
5.56 was designed for a 20" barrel, with a target velocity of 3250fps. quit playing the moron, you know better
2 years ago
Anonymous
>muh le/mil
they're fricking morons. listen to the guy who made the rifle, not the ones who sabotaged it
2 years ago
Anonymous
>listen to the guy who had to spec out a rifle to defeat a steel helmet at 600 yards, not the guys actually using the rifle in real life—not some bureaucrat's fantasy of what combat is like
yeah
2 years ago
Anonymous
if it wasn't for him your dumb ass would be carrying around a 15lb hunk of wood and 20lbs of ammo for it still
I wouldn't bother arguing with someone that takes a screenshot of a picture they already have in their gallery. Especially if the picture is that shit.
Pretty close to 20'' velocity and has nice smooth rifle length gas.
The only reason they picked 18 instead of 20 was because the logistics people thought having two kinds of 20'' barrels would be too confusing.
Rate the level of autism on my build, wanted a GPR and got an 18 in BCM stainless upper which is normally 750ish but my LGS had one for just under 600. Really only got it for the price, knowing more now i would have just spent the extra money for a 14.5 CHF off of BCM’s website. Still happy with the gun for a first AR and just a hair under 2 MOA at 100 yards with this new microprism scope.
>Inb4 needs a light
Yeah yeah im poor and a surefire M600U is 400 bucks
Holy fricking shit it's not that complicated. Set a maximum range for the rifle and pick the shortest length that gives you supersonic performance at the maximum distance with 77gr projectiles. If you intend to shoot the gun beyond 500y then get a 20" barrel. If it's a 300y and in gun then a 12.5" is sufficient. If it's a 100y and in gun get a 10.5". >how far away do I need to deliver a supersonic projectile?
This is the question to ask when evaluating barrel length. If we're talking hunting rifles then the question becomes >How far away do I need to deliver a projectile in excess of 2200fps?
It's not that difficult and can be figured out with some really simple calculations.
pencil 20" weigh as much as 12-14" "govt" profiles, only other argument is maneuverability which is a fricking joke, there are plenty vidoes out there of hajis using m16s from cars without an issue
Anything below 24" wont be able to penetrate level 4 plates unless you have rare ammunition you wont have easy access to, 24 inches is actually the bare minimum.
So a buddy of mine was in the marines for 20 years, I think it was between 1998 to 2018 or so.
He's always wanted an AR but is too cheap to get one.
What build would be close to what he might have used the most if I were to get him one as a gift?
20" is a good length. I agree OP
tired of 20 inch ar gays spamming this board with false info
Clean your room BUCKO
They cleared houses with bolt action rifles in WWII
150 IQ poster
You've never taken a PhD level physics class. Give me a break
Mk.12 is the best, but the M16 DMR can be given to anyone anywhere
>small pp thread
18" is best "
isnt the M16 SDMR just the standard issue M16A4 in the Marines? Is the M16 SDMR an army thing?
no
well what's different
>HHHPH
sorry CHUD, best length coming through
it's too meaty for me. it's built so that even crayon eaters cant break it
>Subverted National Defense: The Picture
reminder that you can just have multiple uppers and you dont have to stick with one barrel length
>poopaloo pops off
>load up kit
>prepare my 20" ar with collapsible stock
>meet up with pals
>see kevin with 2 backpacks
>one for the kit and one to carry his multiple uppers with different barrel lengths to cover all applications
>cant take him into any of those applications because he fumbles around and makes a shit ton of noise
>ambushes and the element of surprise are gone when he's involved
>Kevin weighs almost 350 lbs
>Kevin is also rrans btw
suppressors are just too good to go without. the flash reduction, noise reduction, and comfort shooting especially indoors.
therefore, 14.5 is the best barrel length, because it basically gives you a 20" AR.
Does that added length from the silencer increase muzzle velocity?
No
t. Has no idea how a suppressor actually works
A suppressor is a metal tube with chambers that capture gases from the escaping projectile. They aren't extra barrel length. They are more likely to slow the projectile than accelerate it.
Iirc in real world testing a suppressor will increase muzzle velocity but not by a significant amount, definitely not enough to make up the difference between between 14.5 and 20" and thus, the M16 prevails.
I never understood the 700-950 RPM. Is it referring to different barrel length fire rates, or is it actually completely randomized between those values?
As the gun heats up the gas tube will expand, letting more gas through and causing the rifle to cycle more quickly
t. doesn't know Socratic method. Or sarcasm.
not enough to matter
If all you care about is muzzle velocity, why handicap yourself with a 20" barrel? Why not 22" or 24" or even longer?
do you know of any 24" pencil barrels? serious question
No, because 24" barrels are mostly targeted to varminters who don't care about weight and do care about how fast their barrel warms up, but ADCO (or equivalent) will happily lathe your barrel down to whatever profile you want for a reasonable price.
There should only be 15" AR-15's
20 and 10.3 are the only acceptable barrel lengths
Interesting take. I live in cornfield country, I made this thread cuz I’m thinking of upgrading my go to rifle from a 14.5 with a 1-6x LPVO to a 20” with a 1-8x. Ive already got everything ordered, can’t wait to see how it looks slapped together
Wow, I had no idea my moron AR build actually had a name... Special Purpose Rifle it is!
That's sex
How do you like that acog?
>putting a nice scope on ruger dogshit
lol, lmao
If its 5.56 yes, but I hope we switch trains and one day we upgrade to a more ballistically efficient caliber
Thats not how u say 18in barrel. Just got my upper today with MOE buttstock. To go with 11.5 upper with brace.
Why would I want none of the velocity of 20” and none of the maneuverability of 14.5/16? Genuinely asking
Still close to velocity as 20in while more velocity then 16in. Still manuverable as a 16in, wtf are you talkin bout?? I was actually ordeing a 20in upper and a lower but guess what i sent it back and bought 18in upper last minute
Also pic related for 55gr
That chart is way off. M193 out of a 20" is about 3180-3220, depending on the ammo. Out of a 16", you are getting about 3050 fps. It may not seem like much, but that extra 150 fps means the M193 from the 20" still has bullet upset to almost 200 yards, whereas the 16" only has bullet upset to about 125 yards. Not to mention a flatter trajectory to mid ranges, such as 250-400 yards. And because it's going faster at range, it's bucking the wind a bit better, too.
>that chart, which was generated with a chronograph and a hacksaw, is way off
>these numbers I pulled out of my ass are way more accurate
most target load .223 you're shooting is probably around 3050 yes but m193's spec is literally 3250fps out of a 20" barrel
You're not getting a 150 fps difference between 20" and 16" At most it will be 120, and with most other loads it's actually closer to 100 fps difference. Basically indistinguishable.
with as fast as 5.56 decelerates every inch of barrel you cut substantially reduces its effective range, esp comparing to other rifle cartridges
1. So why 20" instead of 22", 24", &c.?
2. Looking at the procurement decisions made by LE/mil orgs that actually shoot people regularly, 14.5"–16" seems like it's good enough for most realistic use cases—do you disagree? If so, why?
because
u fricking dummy
5.56 was designed for a 20" barrel, with a target velocity of 3250fps. quit playing the moron, you know better
>muh le/mil
they're fricking morons. listen to the guy who made the rifle, not the ones who sabotaged it
>listen to the guy who had to spec out a rifle to defeat a steel helmet at 600 yards, not the guys actually using the rifle in real life—not some bureaucrat's fantasy of what combat is like
yeah
if it wasn't for him your dumb ass would be carrying around a 15lb hunk of wood and 20lbs of ammo for it still
I wouldn't bother arguing with someone that takes a screenshot of a picture they already have in their gallery. Especially if the picture is that shit.
Frick off cousin frickin cracka, da jpg is too big to upload.
Pretty close to 20'' velocity and has nice smooth rifle length gas.
The only reason they picked 18 instead of 20 was because the logistics people thought having two kinds of 20'' barrels would be too confusing.
Nice I just got the like 2 weeks ago.
Wait I'm a moron, you said buttstock.
That is not true, OP. There are also 22" and 24" options to consider once you start chambering for better rounds.
>not using a 2" barrel with a 14" pinned and welded muzzle device
I like my SDMR replica. It's nice.
>Not just because it's the cheapest and easiest replica to make
frick off old frick
Rate the level of autism on my build, wanted a GPR and got an 18 in BCM stainless upper which is normally 750ish but my LGS had one for just under 600. Really only got it for the price, knowing more now i would have just spent the extra money for a 14.5 CHF off of BCM’s website. Still happy with the gun for a first AR and just a hair under 2 MOA at 100 yards with this new microprism scope.
>Inb4 needs a light
Yeah yeah im poor and a surefire M600U is 400 bucks
>Yeah yeah im poor and a surefire M600U is 400 bucks
X300T Is closer to 300 and has most of the same capability.
Not all ARs are 5.56. Some cartridges maximize at different barrel lengths. You're generally correct, but specifically wrong.
Holy fricking shit it's not that complicated. Set a maximum range for the rifle and pick the shortest length that gives you supersonic performance at the maximum distance with 77gr projectiles. If you intend to shoot the gun beyond 500y then get a 20" barrel. If it's a 300y and in gun then a 12.5" is sufficient. If it's a 100y and in gun get a 10.5".
>how far away do I need to deliver a supersonic projectile?
This is the question to ask when evaluating barrel length. If we're talking hunting rifles then the question becomes
>How far away do I need to deliver a projectile in excess of 2200fps?
It's not that difficult and can be figured out with some really simple calculations.
pencil 20" weigh as much as 12-14" "govt" profiles, only other argument is maneuverability which is a fricking joke, there are plenty vidoes out there of hajis using m16s from cars without an issue
I don't need it, but I want that SAM-R
That SAM-R is wrong. They have stainless Compass Lake barrels, not phosphated A4 barrels.
Me too, but the FSP is unobtanium.
t. Male with feminine baby hands.
Anything below 24" wont be able to penetrate level 4 plates unless you have rare ammunition you wont have easy access to, 24 inches is actually the bare minimum.
20” A4 for the win
A4 brethren unite. We will grow tired of winning but we have no choice but to keep on.
>a2 barrel
please go
So a buddy of mine was in the marines for 20 years, I think it was between 1998 to 2018 or so.
He's always wanted an AR but is too cheap to get one.
What build would be close to what he might have used the most if I were to get him one as a gift?
any generic A4gery
Colt, Aero, whatever—a Marine isn't going to notice the difference anyway
Quad rails are an abomination