Some other anon mentioned squeeze bore pistols coupled with lightweight UHMWPE bullets with a metallic insert/rod as a core, and I think hes really onto something.
~horrific wounding inside of SD distances due to high velocity projectile exceeding the elastic limit of tissue, similar to thunderzaps bullets.
~bleeds energy quickly beyond typical SD ranges/after penetrating target.
~squeeze bore allows for adequate pressure, even with ultra light mostly poly ammo
~squeeze bore issue of increased barrel wear is eleminated with low friction UHMWPE
>b-but muh under penetration!!!
As demonstrated with the thunderzaps of old, the theory of ultrafast poly bullets is sound, and that was with a deep hollow point and no metallic insert.
We could have 3500 fps needle pistols bros, and I'm tired of pretending we can't.......
Pic is another NICE THING WE JUST CAN'T HAVE BECAUSE WE JUST CAN'T OKAY?!?! AT LEAST EVERYTHING THAT USED TO LOOK COOL HAS 30 RAILS AND A PORTED SLIDE WOOOOOO
what kind of build up or fouling does this leave on rifling? Does any of it get vaporised and how dangerous is it? What pressures are going on? How is this different from a jacketed wooden boolit? What about conservation of momentum at what range does this start becoming anaemic?
Uhmwpe probably wouldn't have a lot of fouling. It doesn't really stick to anything. It's also just hydrogen and carbon, so it wouldn't be inclined to outgas much either.
This is just armor piercing composite all over again. I think the problem will be dealing with the pressures generated by the squeeze effect, especially in a revolver where flame cutting and cylinder gap are a thing.
It's probably technically possible, though. Getting a barrel made to test it would be a b***h, though.
Something that came up in the last thread was how exactly you'd bond the UHMWPE jacket to the metallic core in such a way that the core and jacket don't separate. There was also the question of how well spin stabilization would work in a projectile with the densest material centralized along its long axis, where its rotation has the least effect.
I think both of these issues might be resolved by a modified version of something another anon came up with in that thread. Consider using the core to establish your ogive at fully tapered diameter, with a thinner rod passing into the body of the projectile. As the bullet passes through the tapered bore it can't extrude past the core, because the core itself is taking up the diameter of the passageway.
This also leaves you with a very front-heavy bullet, which should tend to stabilize itself. I found a patent for a mass stabilized flechette that seems to suggest such a bullet would in fact be stable.
https://patentimages.storage.googleapis.com/c9/2a/cb/4bb38f294f17e2/US3880083.pdf
>I think the problem will be dealing with the pressures generated by the squeeze effect
Funnily enough, I started considering the use of a squeeze bore specifically to address an issue related to chamber pressure. Specifically, polymer bullets are both light for caliber and deform much more readily than jacketed or lead ammunition does, so they result in much lower chamber pressures. This means that they aren't making full use of the powder they're burning, so you're leaving velocity on the table and turning it into muzzle flash instead. A squeeze bore allows you to increase the amount of energy that deformation requires, increasing pressures back into the optimal range for whatever cartridge you've decided to chamber it in. Something like a drop in barrel replacement in a semiauto pistol should be entirely feasible, because as far as the rest of the firearm is concerned it's now running at normal operating parameters.
I'm glad you showed up anon. I have put a lot of thought into this and until you, never considered a squeeze bore.
I'll be back tonight or at some point early next week with some back of the napkin math on the relationship between deformation, pressure and velocity using the data
recorded in his thunderzap video, SAAMI specs, and one of my old engineering textbooks. That should give us a better idea of the ballpark we're working with as far as reasonable velocity goals.
Out of curiosity, why 3D printing vs. ordering some jackets that've been turned on a lathe? Ease of prototyping?
>why 3D printing vs. ordering some jackets
I'm planning on getting some turned that are exact copies of the originals but it's easier to make a homogenous bullet with printing.
>What are the top candidates so far?
The guy was talking about nylon with some copper infused filament in the center. I'm dumb with this kind of thing so I'm just listening to him.
The pressures can be managed with the severity of the squeeze, and weight/load of the projectile. Like the other anon said, UHMWPE would likely have minimal fouling, if any as is both extremely abrasion resistant and has a very low coefficient of friction, especially compared to something like wood.
I posted the op pic because I think it's cool, not to say these would work best in revolvers, although I imagine they would with how well thunderzaps worked in snubs. Pressures can be predicted and accounted for via bullet and barrel design.
This type of firearm/ammunition design would be a significantly vertical improvement over what we cc now as far as wounding and threat stoppage goes.
Wood's metal or a related alloy, some turn into liquid at tempatures as low as 117 F. Using barrel friction you could have it turn liquid as it compresses then solidify as it reaches the end of the barrel assuming you had the right allow:
https://en.wikipedia.org/wiki/Wood%27s_metal#Related_alloys
Yeah I'm sure that'll do wonders for stability and accuracy.
If it reverts to a solid when it finishes compressing there should be no problem, the ratios of those alloys are well known so making one that is liquid while being compressed but solid when it hits the second half of the barrel is no problem. Just make it a pepper box to avoid problems with the barrel heating after the first shot. A semi auto pepperbox for maxium autisim.
>he doesnt want to shoot liquid metal bullets
>Cerrolow 117: 117 degrees melting point
How many rounds would you have to fire before the next round was that hot out of the barrel? If you put it in a copper jacket it wouldn't 'spill' so it would be contained liquid when it hit but cool off as it penetrated flesh turning solid, i would love to see the would ballistics on that. Also the rage face of the doctor who has to dig out the fragments if the target lived.
It's me and I'm actually talking with a chemist buddy who's big into 3D printing and we've been talking about duel material bullets with a denser core made out of something that isn't on the AP list.
What are the top candidates so far? I would think stuff like harder brass alloys, harder zinc alloys, maybe copper..
I know it breaks the rule of higher density material, but I wonder about increasing the diameter of the rod a bit and using 6 or 7 series aircraft aluminum or a hard ceramic sphere impregnated in the plastic.
Basically any metal would be AP to soft armor at that speed, list or no list. Wether made of lead or Aluminum or even something like zinc or nickel, the core is probably going to go straight through a man.
>Squeeze-bore
What's the difference between these and progressive depth rifling like found on the 1853 Enfield rifle musket or the progressive depth ratchet rifling on the Kerr rifle? You might enjoy English Patent #4348 (1861) for his unique rifling design. probably the best rifling system ever created. You won't get anything a accelerating to 3500FPS in a short barrel though anons, its just not long enough! This is your constraint with handguns, always ways and always will be, to be handguns they have to conform to what the average mans arm and wrist can do, turns out that's rough the recoil of a 44 mag at most and a howdah or 7 inch revolver barrel (or you are getting too heavy to point for any decent time). So you need something that can accelerate a light boolit to thousands of feet a sec in lets say at best a 7 inch barrel? Its not happening, Now these things may still have a place some how but I don't see it without a different load, you may want to look at hilti nail gun blanks for powder inspiration because its going to be fricking fast. Honestly I'm not sure you can actually make a more perfect practical handgun solution than a pair of five inch barrel 44 mag side by side double trigger box locks but that's just me and I admit I am peculiar and set in my ways
>English Patent #4348
https://www.bl.uk/help/find-early-british-patents
>You might enjoy English Patent #4348 (1861) for his unique rifling design. probably the best rifling system ever created.
https://vringblog.wordpress.com/2017/02/01/so-many-ways-to-skin-the-cat/
“Kerr’s rifling is a six groove ratchet with the top of each tooth cut off to form a flat land. The part of the system which Kerr registered was not the form of the rifling itself, but that a section of it for several inches at the breech was to be perfectly straight. This was in order to allow the bullet to upset completely into the grooving before beginning to rotate up the barrel, thereby assuring non-stripping and uniform upsetting. Kerr’s was a somewhat undersize .451, nominally, but as with so many others it accepts .457 bullets quite readily in most cases. The twist of the rifling is gaining for a short space ahead of the straight portion, but by the middle of the barrel it stabilizes at 1 in 20. The depth of the rifling is progressive, becoming shallower towards the muzzle, which greatly contributed to its non-fouling tendencies.”
>What's the difference between these and progressive depth rifling
Progressive depth rifling is different in that the bore diameter itself is a constant throughout the length of the barrel, though the groove diameter continuously decreases. A squeeze bore- as its name suggests- is a tapering of the bore diameter.
>You won't get anything a accelerating to 3500FPS in a short barrel though anons, its just not long enough!
Consider that Thunderzap rounds are already pushing 2900-ish fps out of a sub-5" barrel. And that's with its less efficient powder burn and lack of any bore tapering whatsoever. 3500fps isn't an insane ballpark to aim for.
>Machining a squeeze bore barrel will be exponentially more expensive than a regular barrel.
In the case of a hammer forged barrel, all you're doing is changing the geometry of the mandrel. The additional internal geometry will make turning a barrel to shape more complex, but not exponentially so. A squeeze bore barrel will be more expensive than a straight bore counterpart, but to say it is prohibitively so out of hand is defeatist.
>Making custom plastic bullets will be exponentially more expensive than even high-end self defense rounds.
During initial prototyping, absolutely. But at similar scales, you're working with a cheaper material that's easier to work and induces less wear on its tooling. There's a reason why plastics are so prolific in consumer products, anon.
>It's a neat idea in theory, just like all the others that have come out and stuck around for a few years before ultimately failing because of economic inviability.
This is still a realistic prospect.
it would be cool if the squeeze bore portion could just be threaded onto a normal barrel. Like a shotgun choke.
worked pretty good for the bongs
Short of having to solder on and then turn to size copper driving band(s) around a sub-cal core material, I wonder if a hose crimping die could make a precise enough crimp. Perhaps a sigle copper band, crimped in the center leaving space for something like a two-piece polyethylene insert "(" and ")" would work?
It's a moronic idea for gun autists doing a "what if". It isn't something that's commercially viable. Call it defeatist all you want but there's a reason that they went out of fashion in the 40's.
It's infinitely cheaper & faster to make sabot sub-caliber rounds than it is to deal with the recoil & bore wear of a round travelling twice as fast.
>But everything at scale is cheaper than one offs!
No shit sherlock, pretending like this niche bullshit will ever supplant the enormous supply chain for lead bullets further solidifies your moronation.
The future is locally handloaded micro batches of schizo bullets.
>The additional internal geometry will make turning a barrel to shape more complex, but not exponentially so
on a CNC you would literally have to add one line for taper comp, unless there's something firearm specific i am overlooking
Rifling a taper would be difficult. A normal pistol length barrel would be easier than a rifle length barrel, but perhaps a short inch and a half long smoothbore muzzle device would be the ticket. Lets you use a normal threaded barrel, and still get the benefits of squeeze bore projectiles.
So difficult that the Brits had it figured out for their service rifle back in 1870.
They're never going to supplant regular pistols.
Machining a squeeze bore barrel will be exponentially more expensive than a regular barrel.
Making custom plastic bullets will be exponentially more expensive than even high-end self defense rounds.
It's a neat idea in theory, just like all the others that have come out and stuck around for a few years before ultimately failing because of economic inviability.
yes but you don't belong here, you are not one of us. As a side not even progressive depth rifles like the enfield 1951 DO NOT have their original progressive depth barrels in reproduction even when made by quality first like pedersolli. Only a few thousand people worldwide own original real long range progressive depth rifles (typically ker, turner, alexander henry other customs from similar makers). They are all in the sniper community mostly retired . You rarely get to see these guns or shoot them
>horrific wounding inside of SD distances due to high velocity projectile exceeding the elastic limit of tissue, similar to thunderzaps bullets.
>>b-but muh under penetration!!!
>As demonstrated with the thunderzaps of old, the theory of ultrafast poly bullets is sound
Link to tests demonstrating this, particularly the adequate penetration?
Thunderzaps were drilled out into hollowpoints because a FMJ shape had significantly higher penetration.
That doesn't prove anything. Glaser Safety Slugs were another old meme self defense round that managed to stick around for about 40 years, and there's tons of gel tests showing that those absolutely fail to meet any penetration standards.
>Glaser Safety Slugs
I can't believe they still sell those things. The 80s and 90s were full of gimmicky trash with all kinds of wild claims but most of it has long since vanished.
>I can't believe they still sell those things.
They don't. They were finally discontinued sometime in the past few years.
Every era is fully of gimmicky trash, anon. It's not just the 80's and 90's.
Nah, that was the heyday of goofy meme bullets. MagSafe/Glaser/BeeSafe frangibles, Thunderzap and other similar plastic bullets, nylon coated aluminum bullets I can't remember the name of, BATs, Pingrabbers, Ultra-Shok and Omni-Shok, Devastators and Exploders, the list goes on and on.
I'm well aware of the meme bullets from that era but it's not like that is anything new.
A hundred and twenty years ago you had goofy shit like picrel which was supposed to spin while firing due to air passing through the angled holes inside it, wooden-tipped hollow points like W. Greener's expanding bullet, hollow spherical slugs (which might or might not be filled with explosives), shotgun slugs that had a self-steering rudder at the back, a strange contraption that was supposed to make shotguns shoot denser patterns by trapping the shot in a wire mesh "cage", etc.
And today we have meme crap like RIP, Dragon's Breath and all the other silly shotshells from companies like War Wolf, etc. And a lot of the meme bullets people associate with the 80s/90's are actually much earlier. KTW's infamous teflon coated bullets date to the 1960s.
Not that anon, but modern ballistics gel testing for handgun ammunition didn't start until the late 80s, and it wasn't until the 2000s that normal people started being able to look at how a variety of ammunition performed.
Thunderzap definitely does not have adequate penetration if you're looking at the FBI standards. It dumps all of it's energy almost immediately within 4"-6" of hitting something.
This is good IMO because it will barely penetrate drywall and has no chance of zipping through a person. And according to old forum posts you can catch it in your hand at 100 yards. So it won't fly a mile and hit someone's house.
It shouldn't be used in place of standard ammo but it has a niche.
Seconding this. Where's the proof of any of these claims?
You misunderstand me, I am not claiming thunderzaps met the fbi penetration standard, but that they don't need to in order to work well.
With a round nosed bullet containing a metallic/ceramic insert, it very well may meet the fbi standard, although again, this is not mandatory for it to work well. At 3500-4000 fps, you're going to be turning cantaloupe sized areas of tissue into hamburger.
I will try to find the 2 cases I know of where thunderzaps were used in a self defense scenario.
I agree about it defeating soft armor regardless of the penetrator material, the all poly slap shot slugs do it with no metal at all.
I do disagree about the penetrator tending to zip clean through tissue, as most any materials break up or deform at these speeds, although I could be completely wrong about that.
>I agree about it defeating soft armor regardless of the penetrator material,
Speed is king, but I have my doubts a solid polymer slug, even moving at 4kfps is capable of defeating a poly-backed soft armor material at close ranges. The atlas people show copper can, below 2300fps though.
Indubitably
>I am not claiming thunderzaps met the fbi penetration standard, but that they don't need to in order to work well.
>With a round nosed bullet containing a metallic/ceramic insert, it very well may meet the fbi standard, although again, this is not mandatory for it to work well.
lol
>I will try to find the 2 cases I know of where thunderzaps were used in a self defense scenario.
The ones that are 4th hand hearsay, at best, with absolutely 0 supporting documentation or proof that they even happened about a mugger getting his arm blown off and a guy in South Africa getting all the flesh stripped from his ribcage?
i've never heard of squeeze-bore until today which makes me think its some archaic design that faded into obscurity for a reason.
Initial OD: .357" (0.0091m)
Tapered OD: .224" (0.0057m)
Temperature: assume 100C, will probably be higher in actuality but frick it that's the data I found.
Engineering strain = (Lf-L0)/L0 = (.357-.224)/.224 = 0.59375
True strain = ln(1+engineering strain) = ln(1.59375) = 0.46608
Graph stops at 0.24 because material stress approaches a constant value as strain increases (flow stress), so take stress value at maximum depicted true strain.
From pic rel, flow stress value = ~30MPa (~4351PSI)
So what's the pressure behind a Thunderzap?
Anon got an average fps of 2864 (or 872.95m/s) out of a 4 5/8" (0.117475m) barrel, pushing a 35gr(0.0022kg) projectile.
Given the final fps and pretending that the bullet experiences zero drag after precisely the length of the barrel, we can kinematically solve for first the acceleration, from there the force, and from there the pressure.
With values of 872.95m/s for final velocity, 0m/s for initial velocity, and 0.117m for distance we get a value of 3256588.4722 m/s2 for our acceleration.
Given that f=m*a, a value of 0.0022kg for m and the above for a, we see that f = 7135.53N
With our bore of 0.0091m we have an area of pi*(0.0091/2)^2 = 0.00006504m^2
Pressure is force over area, so P = 7135.53N/0.00006504m^2 = 109709870.849Pa, or 109.8MPa, or 15912.07PSI. According to SAAMI, the maximum average pressure for .357 magnum is 35000PSI.
That means that even squeezing down from .357 to .224 (adding our calculated 4351PSI for additional deformation to the found Thunderzap pressure value), we should be well under maximum pressure.
>(1/2)
You just calculated an average chamber pressure and compared it to a peak pressure. (The "average" in MAP refers to averaging over multiple rounds tested, not averaging over the acceleration as you're doing.)
I didn't average it over the acceleration, unless you're referring to the fact that the basic kinematics equations assume a constant acceleration. I calculated an average chamber pressure based on the average velocity anon found shooting Thunderzaps out of his revolver (watch?v=yh8O9xL-G2Y) and compared it to the MAP for .357 magnum. I'm aware the MAP averages over multiple rounds and that the sample size I'm working with is too small to be truly rigorous. That being said, it would have to be some really rotten luck for a truly representative average pressure to be significantly higher to the point where there's no value in trying to make up the difference, and it gives us some idea of what a full pressure polymer round might be flying at. The use of "SAAMI max for .357 magnum" was inaccurate, 35000PSI is the SAAMI MAP.
All that being said I'm the wrong kind of engineer to speak authoritatively on this math, have I misunderstood your criticism?
>assume a constant acceleration.
Exactly. Calculating with that assumption gives you the average pressure, and if the assumption is accurate, the peak pressure is the same.
The problem is, in real firearms, pressure and thus acceleration varies dramatically, so the assumption is not valid, and while the average pressure you get that way is still valid, the peak pressure is generally much higher.
I'm not really concerned with sample size, I was just explaining that because I thought you might have misunderstood MAP as referring to average pressure as opposed to peak pressure.
Keen eyes will note that our deformation pressure value has a problem; It's in force per unit area, but we really want force per unit volume, since we're deforming a radially symmetric profile rather than truly distributing a force across a 2D surface. In order to model this, let's pretend we're deforming thin circular slices one after the other. The thinner each slice, the more accurate this estimate will be, so let's make them super thin. Infinitely so, in fact. Since each slice is infinitely thin, so has no volume, but retains its surface area. So, depending on the number of slices (the length of the solid to be deformed), we can scale the pressure up or down. Anyone who's taken a little bit of calculus will recognize that we're taking the integral of the force per unit area with respect to volume. With the radius of the cylinder to be deformed fixed that means it is only dependent on the length of the section to be deformed. In other words, it is possible to calculate a length that will safely bring us to the cartridge's SAAMI maximum pressure.
At this point We have successfully established three things.
>1. Thunderzap rounds, despite all their speed, are well under maximum pressure specs
>2. UHMWPE can be reasonably subject to serious deformation in a firearm, making it suitable to use in this application
>3. There is a direct relationship between the full bore, full taper diameter, and length of the projectile to be deformed that allows us to manipulate pressure
>(2/3, whoops)
>Thunderzap rounds, despite all their speed, are well under maximum pressure specs
That makes me a lot less nervous about making my own.
There's room for some concern because I was working off the SAAMI value for .357 and IRL the round absolutely has bled some speed before it hit the chrono so pressures are higher than calculated, but overall you shouldn't be terribly concerned I don't think. Slap a safety factor you're comfortable with on there and use a long string for the first couple rounds.
I'm going to skip the calculus to determine the proper length of the deformed jacket for tonight because I've already started drinking and I want some quick dopamine. Let's hold the weight of the Thunderzap constant and assume we have a deformed jacket length that'll bring us right up to the edge of the SAAMI max for .357 magnum, 35kPSI at full bore. How fast will that go?
Well, let's work backwards.
35kPSI = 241316505.26Pa
241316505.26Pa*0.00006504m^2=15695.23N
15695.23N/0.0022kg=7134195.45m/s^2
And then back to the kinematics solver, and we find that with the same barrel length and an initial velocity of zero we now see a final velocity of 1294.67m/s or 4,247.6fps.
Not bad for a four and five-eighths inch barrel.
>(2/3)
This was the last one for my calculations, I just fricked up my greentext numbering (again).
Stupid
You're chasing marginal performance benefits at the cost of building an entirely new logistical ecosystem. Why buy a new weapon and ammo that will cost significantly more for barely noticeable performance benefits?
>You're chasing marginal performance benefits
There is no world where a pistol spitting out a projectile at four thousand fps is a "marginal performance benefit."
>at the cost of building an entirely new logistical ecosystem
This is self defense ammo for the average concealed carrier and we're working within the limits of existing calibers. Picking up a couple boxes of a different kind of ammo in a caliber you already have stockpiled isn't that big of a deal.
>Why buy a new weapon
Muzzle device or compatible barrel, not a new weapon.
>ammo that will cost significantly more for barely noticeable performance benefits
People already do this for self defense ammo, which is predicated on a much narrow margin of performance. What, your hollow point expands a little more? Cute, this hits flesh at rifle speeds.
Additionally and most importantly, it's fun.
because it's cool
It's not stupid when you have to make your own bullets and cartridges in a SHTF scenario.
Let's say you shot all your regular ammo.
Where are you going to get more primers?
You can make powder or scavenge powder from other ammo you can't shoot since it's the wrong caliber.
However, you could use a .223 rifle slug in this gun by wrapping it in UHMD. Or just turn out some rods on a lathe or cut presized rods for ammo.
Also an electric ignition system with a battery/solar panel would solve for no primers.
For that matter, you might be able to go caseless or poly cases. There's no shortage of plastic laying around. Brass is going to be hard to come by later six months after the downfall of society.
Also, I suspect the ballistic rifling of the jacket is gone once it strikes a target and explodes. So there's less evidence on what kind of gun or who shot it perhaps.
>Fabricate expensive tapered barrel so you can make meme ammo in a SHTF emergency
vs
>just buy more ammo with that money
this person is honest.
>thatthingyoujustsaiden
>It's not stupid when you have to make your own bullets and cartridges in a shtf scenario.
lol
lmao
I don't understand these guys.
Being able to generate wounds that exceed the elasticity of tissue is the main reason rifle wounds tend to be so much worse than pistols just poking a hole.
That's a huge improvement, not marginal at all.
I find the concept of a squeeze-bore pistol absolutely absurd, but please make this a thing.
If I were to offer any suggestions, thread the barrel of a revolver to accept a squeeze bore attachment, you could think of it being like a choke for a shotgun. This way it would be easy to experiment with new squeeze bore attachments and in the event the squeeze bore is designed incorrectly and has a bullet stuck in it, it might be possible to remove it anyways and attach a new one.
Standard sized barrels can already break 3kfps with Teflon bullets though.