Given current design and manufacturing capabilities any guesses or actual studies as to the smallest projectiles that could be produced to meet standards? If so what are the limiting factors? I'm curious about both pistol (~1000fps MV) and rifle (2700-3300fps MV) projectiles.
Please note I am not asking about any particular cartridge, firearm, etc. that already exists.
Since the IWBA/FBI test don't require expansion and reward penetration and retained weight with little to no penalty for super deep penetration and focus on barrier "blindness" a hard non expanding projectile could pass the test pretty easily at the velocities you listed. As long as it didn't break up or was too excessively lightweight. A hard and pointy projectile is going to do better at barrier penetration at any reasonable velocity. Consider earlier armor piercing ammo for handguns.
Please define "smallest"--what physical parameter are you referenceing (mass, diameter, length, etc...)?
Facts matter...Feelings Can Lie
My apologies. I see that I did not specify my question nearly as well as I thought I did and left things far more open ended than intended. I'm just thinking conventional mass producable bullets, ammunition, and semi auto firearms.
I am asking about reliably expanding projectiles and not ball or AP ammunition.
Smallest diameter. I should clarify further that the "pistol" projectile should be short enough to be fired from a conventional semi-auto pistol.
... I had implicitly assumed that the smallest mass projectile would also be the smallest diameter projectile. It's this not the case?
Thank you for indulging my curiosity.
Admittedly I'm cherry picking here, but subsonic .300 BLK bullets are typically 200+ grains, and .308" diameter. .380 ACP @ 95 grains bullet weight is .355"/.356" diameter, so I don't think that's necessarily a valid assumption.Originally Posted by X9VlmF8m
A lot depends on what the projectile is made of solid copper/gilding metal is lighter than lead core, which is lighter than tungsten core, etc..."I had implicitly assumed that the smallest mass projectile would also be the smallest diameter projectile. It's this not the case?"
Facts matter...Feelings Can Lie
Everything will “expand” (read fragment) given enough velocity. I guess I’m also not understanding the question - but I think you’re asking,
“What is the smallest diameter bullet which can reliably expand, within our manufacturing abilities at present?”
I recognize it’s a theorerical question, but the answer is probably reflected in empirical data. The most reliable expanding bullets to date (that don’t fragment, as frequently) appear to be solid copper, pre-scored type projectiles like the Barnes bullets. In that realm, any of those bullets from approximatelt ~.30”+ in a handgun appear to reliably expand in your given velocity (1000 fps).
In the rifle realm, the .17” caliber bullets in the HMR appear to reliably expand. It is much easier to build a reliably expanding high velocity bullet. More velocity typically increases penetration and expansion - to the point of bullet fragmentation. A solid copped - Barnes-like projectile at 3000 fps would be a very good expander and penetrator, virtually regardless of caliber (though larger calibers and heavier bullets will expand and penetrate more, all else being equal).
Last edited by RevolverRob; 01-07-2019 at 01:37 AM.
Given well designed bullets at identical velocities I believe we can say that a 90gr 7.62mm projectile would perform poorly compared to 200+gr projectiles and 200+gr .355" projectiles would out-perform 90gr .355" projectiles so your comparison isn't valid.
Due to the existence of successful .300 Blackout loads we can say that:
-- 7.62mm sub-sonic lead/copper JHP rifle projectiles that pass IWBA/FBI test standards while expanding reliably, consistently, and significantly can be designed and produced.
-- Can 7.0mm sub-sonic lead/copper JHP rifle projectiles that pass IWBA/FBI test standards while expanding reliably, consistently, and significantly be designed and produced?
-- Can 6.5mm sub-sonic lead/copper JHP rifle projectiles that pass IWBA/FBI test standards while expanding reliably, consistently, and significantly be designed and produced?
-- Can 6.0mm sub-sonic lead/copper JHP rifle projectiles that pass IWBA/FBI test standards while expanding reliably, consistently, and significantly be designed and produced?
...
At some point you hit the limit due to the inability to practically produce bullets that small, or the inability to rifle a barrel with a twist fast enough to stabilize bullets that long, or the inability to design hollowpoints that small, or simply by no longer having enough mass to meet the goal, or other constraint I haven't thought of.
What is that limit? What is the projectile weight at that limit? Is there a larger caliber that meets the goal with a lighter projectile?
I feel like you're moving the goalposts a bit with all these assumptions you didn't state in your original post. Regardless, I was merely trying to point out that diameter and mass are not necessarily tightly linked the way you seemed to think and that it's definitely possible for a long, skinny bullet to have a larger mass than a short, fat bullet.
So you want theoretical ballistics on vaporware?
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