What cans are we using on SBRs and AR pistols?

[WillBrink]

Maybe the response wasn’t for you?

As the OP, unless quoting someone, I will assume it's directed me.

You’ve already had a smattering of SMEs chime in to tell you about physics, gun handling and that very few cans are rated for a barrel that short (you know those physics you are dead set on ignoring).

I ignored nothing what so ever, no one offered any "physics" that I was unable to address, and or was not aware of, and several claims made such as velocity below expansion thresholds, etc, were easily shown to be incorrect dependent on the load. The most relevant comment as it applies the topic, was whether the velocity reaches that capable of the terminal ballistics capable of wounding mechanisms via cavitational forces of temp-> perm cavity. That was discussed, was not settled, but not the least bit ignored.

Sources supplied by one member was in fact countered by their own source (that is, the source claim the effect happened at lower velocity with soft point hunting rnds) but I think that one needs more exploration and research. Claiming I "ignored" the physic supplied false. I'm not an SME on terminal ballistics, but I can hold my own with anyone here on that topic, and have researched that one for decades, and research, is in fact my lane.

Gun handling, lots of members are SMEs, I am not. They didn't seem to offer any thoughts that seemed counter to my uses/goals. If there was something specific I missed on that, didn't address, point it out. That's how I/we learn...

Can rating, spoke to someone who is an SME on the topic and they said that's a liability issue vs functional issue, or safety issue per se and have put lots of rnd through all manner of barrel lengths short and longer than 7.5, without any issues, with usual caveats like cans with more back pressure, etc. They did recommend sticking with rated cans due to possible warranty issues, not functional nor safety. I can't confirm accuracy, as I'm not SME on cans, hence the OP asking some Qs.

Also you’re title is misleading. When you say ‘SBR’ people may think this thread was going to discuss useful weapons. You should rename it ‘VSBR’ so people know it’s a thread about range toys.

And again, I'd respond utility of your post of no value other then to (claim falsely) that I ignored the responses, and that's simply not accurate, especially as it pertains to the physics/terminal ballistics aspects.

[Eurodriver]

>wants a rifle for ***self defense***
>content with the minimum acceptable velocity for a limited type of projectile
>sacrifices increased terminal performance, increased lethality, noise reduction, concussion reduction, flash reduction for…?

Yes, you found one sentence, in an entire document about increased velocity in rifle rounds that makes them more lethal, that said velocities at ~1800fps expand with some cavitation.

What about hydrostatic shock?

Hydrostatic shock, in bore sizes from .243” up to .338”, begins to lessen at impact velocities below 2600fps and most modern high velocity sporting cartridges including the magnums gradually lose shocking power beyond 300 to 350 yards. Of the thousands of animals harvested during TBR tests, 2600fps has been the most common cut off point with repeatable results (reactions) occurring when deliberately testing the impact velocity of 2650fps versus the impact velocity of 2550fps.

Note that hydrostatic shock requires more velocity with a lighter round…

https://www.ballisticstudies.com/Kno...20the%20better.

The simple fact is that when bullet weight and type are the same - more velocity is exponentially better. You’re sacrificing what your rifle’s sole purpose is for absolutely nothing of value.

[WillBrink]

>wants a rifle for ***self defense***
>content with the minimum acceptable velocity for a limited type of projectile
>sacrifices increased terminal performance, increased lethality, noise reduction, concussion reduction, flash reduction for…?

Claimed sacrifices are worth the squeeze for what I wanted, as already explained...

Yes, you found one sentence, in an entire document about increased velocity in rifle rounds that makes them more lethal, that said velocities at ~1800fps expand with some cavitation.

What about hydrostatic shock?

You're now confusing topics. I will repeat yet again bro. You had stated the velocity below required for expansion. That is false with modern loads, and didn't come from one sentence in a doc, you supplied. That came from the various ammo manufacturers, such as Barns, Federal, and Speer. 1800fps you say? 2400+ fps is consistent from 7.5, and even shorter, which to repeat, well above the required threshold for those loads for penetration and expansion.

A for cavitation effects, that's the sentence you refer to from the doc you supplied stating that hunting rounds/soft tip rounds, have similar results at lower velocities. Regardless, I said that's a legit topic of concern but are we claiming 2400+ fps is insufficient for that effect? Of course heavier bullets will be slower, but all will be above required velocity for the effects.

Note that hydrostatic shock requires more velocity with a lighter round…

Indeed, as well as the design of the bullet...

https://www.ballisticstudies.com/Kno...20the%20better.

The simple fact is that when bullet weight and type are the same - more velocity is exponentially better. You’re sacrificing what your rifle’s sole purpose is for absolutely nothing of value.

I don't view it a rifle, but a PDW, for SD/HD distances, and compared to any pistol or PDW like the 5.7 P90, it's not even close. You continue to ignore modern bullet designs.

[Eurodriver]

How am I ignoring modern bullet designs? They expand.

If all you care about is expansion a .45 ACP HP round will penetrate >12” and expand way more than any .224 bullet. The APC45 is great and the barrel is less than 7”

[WillBrink]

How am I ignoring modern bullet designs? They expand.

Different bullets are designed to expand at different velocities, and for the 901182 time, modern designs from various manufactures designed to penetrate and expand at velocities well below numbers you continue to claim. So, either you're ignoring that fact or don't understand it.

If all you care about is expansion a .45 ACP HP round will penetrate >12” and expand way more than any .224 bullet. The APC45 is great and the barrel is less than 7”

"What about hydrostatic shock? " - Eurodriver

You again ignored my comment on that issue, which is the only legit issue in this discussion of terminal ballistics here:

"...we claiming 2400+ fps is insufficient for that effect?"

Specific to that issue, if anyone wants to chime in and further learn me on that issue, or has some good resources, etc, I'm all ears.

[georgeib]

I think what Euro is getting at is that you're giving up the advantages a high velocity rifle cartridge offers (hydrostatic shock, huge stretch cavity), ballistically, and exchanging them for a TON of blast and noise. I think his logic holds up. If expansion and direct tissue damage are your criteria for measuring efficacy, you'd be better off with a PCC, as that is all you get with pistol calibers.

ETA: IOW, by going with a 7.5", you've basically turned a rifle cartridge into a pistol cartridge ballistically, so the additional noise and blast result in a net loss overall.

[MegademiC]

300blk is preferred because you get similar if not better performance with less flash, concussion, and you can silence it easily.

[WillBrink]

I think what Euro is getting at is that you're giving up the advantages a high velocity rifle cartridge offers (hydrostatic shock, huge stretch cavity), ballistically, and exchanging them for a TON of blast and noise. I think his logic holds up.

Then you may want to read my responses in more depth brother. He supplied no evidence for that and or I addressed the trade offs

If expansion and direct tissue damage are your criteria for measuring efficacy, you'd be better off with a PCC, as that is all you get with pistol calibers.

ETA: IOW, by going with a 7.5", you've basically turned a rifle cartridge into a pistol cartridge ballistically, so the additional noise and blast result in a net loss overall.

Please take a closer look at my responses. Specific to your comments, are we saying the hydro static wounding mechanisms don't take place at 2400+ fps?

FYI, the hydro static wounding mechanisms of typical FMJ in 5.56 is very high, but again (1) is 2400 fps insufficient for that effect? and (2) modern bullets designed by major manufactures require lower velocities for that effect (3) bullet design per #2, play a important role in that effect and modern manufacturers well aware of that...

[WillBrink]

300blk is preferred because you get similar if not better performance with less flash, concussion, and you can silence it easily.

Agreed! I did address why I went with 5.56 in this thread now, and a 300blk upper likely in my future.

[MegademiC]

You dont get acceptable performance from much in a 7.5" 223 barrel. The only load I know if is the 50gr tsx.


https://youtu.be/31oE-_ZFJGs

Agreed! I did address why I went with 5.56 in this thread now, and a 300blk upper likely in my future.

Points 2, 3, and 4 of that post are false from what I can tell. Besides tsx, what is giving you > pistol performance? The vid above shows on par or worse than pistol.