Ok. Im pretty sure we all know that out of a SBR, the 5.56 round has very little effective fragmentation range because of the short barrel.

So I was thinking. Could you use a faster burning pistol powder to get higher velocities from a SBR? Would this be safe? I do not reload, but I plan on getting all of my grandfathers old equipment once I get a place to put it all.

So, what do you think about the idea?

Better people to ask: http://www.ar15armory.com/forums/Reloading-Armory-f16.html

Damn, I forgot about that forum. Can a mod move this please?

to gain velocity one must either increase chamber pressure or lighten the bullet...... a person is stuck with only so many variables because no matter the length of barrel the chamber can only withstand so much pressure......

Well that's about that. I thought I could add something here.
I use the slow burners in my 44s and 454. I've been playing with some faster burning powders because with the slow burning powders you waste a ton of energy in a giant light show at the muzzle.
The problem is chamber pressure. The only thing you can really look for is a reduction in muzzle flash without a great gain in velocity.
If you want speed then you are going to have to give the ladies what they want. Inches.
I like the SBR and would like to do a 7.62x39 or a 10mm. The idea of the $200 plus other stuff I'll stick with 16.
After a lot number crunching and think I'm going to play with the 6.8 on a heavy 18.
Stoner design the system around a 20 barrel with a slow twist and a 50/ 55 grain bullet. The idea was for the projectile to hit, self destruct/ tumble through the body and create a monster wound channel. Sooooo.
We have fast twists with heavy bullets?

^^^ Pretty much nailed it.

Unless some company wants to create a much harder chamber to allow for increased pressure then there is just a limit to what you can do.

They do make special rounds with increased power. Called proof rounds they are for armories to test chambers on new guns. Darn sure I wouldn't want to fire one of those holding it. The factories load the new rifles into vices inside a steel box and fire into a water trap. Then they fire one proof round and send it to the QC lab to look for chamber cracks.

I have a couple proof rounds. Red painted tips and red painted primers. Got them as part of a much larger swap of gear. If I ever fire them they will be my last desperate hail mary rounds. By then I'll have far larger problems than worrying about my AR blowing up in my face.

True about the original design and intent of the AR15 and .223 Rem/5.56mm. They were the same round at that time.

The newer twists with newer ammo designs help some even with an SBR. I wouldn't use a round that depends on fragmentation in an SBR, at least not a M193 spec or M855 spec. Mk 262 will fragment farther than M193 and will beat M855 by a mile.

Any of the TAP rounds would do well in an SBR as would soft points.


As for reloading info, I'll leave that to you guys. AD, do you still want this moved?



TS

Guys,

I chrono'd WCC 88 55 gr ball at 2647 fps from a 11.5" RR M16 bbl. The typical Winchester load uses something like WW748 as a propellant. I have used a lot of AA DP2200 as a propellant. It is MUCH faster than WW748. (H335 is about halfway between DP2200 and WW748.) My standard load for 20" barrels chronos at 2605 fps form the same bbl. Is very accurate but does generate quite a muzzle flash.

Now ... I do NOT load special stuff for the shorty! I do have longer barreled rifles and I would NOT want to accidently fire a specially loaded cartridge for shorties in a 20" bbl.

My experience suggests it is probably possible to get a little more velocity with a faster powder but there would be a risk in shooting that ammo in a longer bbl ... and the flash would be severe! Not worth the risk and flash in my humble opinion!

If one wants a round that is more impressive at impact, I'd suggest changing the bullet to something like a 55 grain Nosler Ballistic Tip! They open pretty violently.

Thanks guys. I guess Ill just stick to the hollow points and soft points in my SBR.