.223/5.56 out of an 11 inch

[Shawn.L]

i was looking at a SBR with a 11 ich barrel online and got to wondering.

What kind of ballistics can you possibly get for this round out of that little itty bitty barrel???

And if you did use one in a offensive/defensive manner what kind of load/bullet weight/ect would you use???

Just got real curios as to how useful this could be.

[Atomic Dog]

Would be loud in a hallway with a SBR upper. And the rounds might tumble making a suppressor damage very likely (not to mention increased pressure)



Personally, the only SBR's AR I would use would bae a 9mm or .22




Take this with a grain of salt as I don't own anything of the sort.

[LowCapacity]

Would be loud in a hallway with a SBR upper. And the rounds might tumble making a suppressor damage very likely (not to mention increased pressure)



Personally, the only SBR's AR I would use would bae a 9mm or .22




Take this with a grain of salt as I don't own anything of the sort.

Without enough twist in the rifling the heavier bullets won't stabilize but I don't think they'd start tumbling as soon as they exit the barrel. I know theirs some SBR AR guys here so they'll chime in.

[Kaos]

FWIW - a lot is going to depend on some of the variables you're asking about. If you want this for defensive every thing I've read is saying heavy bullets (70+ gr) - hornady tap and a 1:7 twist ratio.

Defensive situations aren't occuring out at 100 yds (generally) but if you look at some of the tac videos out there...what are the guys using? Chris Costa of magpul dynamis runs 11.5" on his SBR if Im not mistaken, and from what I've seen on the video they're nailing targets out at 50 yds.

If you're thinking AR for defense, thinking MOA becomes less of a reality and thinking COM becomes reality. The SBR'd AR becomes even more useful IMO because a suppressor on the end doesnt turn the gun into something ungodly long.

What I am planning is pretty much what you are.

I will be running 11.5" with a mid length gas system and larue rails to normal mid-length uh....length. Normal FSB with a flash hider (until I get a suppressor). I use my VFG as a hand stop only..so the light will be on the left in an offset mount at about 9-11 oclock. Aimpoint CompML2 up on the top with a larue BUIS.

Im still torn on stock selection.

[carcass]

I have an SBR built with a CMMG 10.5" upper on a RRA lower. The twist rate is 1:7 in the barrel. I have an AAC M4-2000 QD suppressor mounted on it. I've never had a baffle strike. I checked with AAC prior to using it--they say they will not warrant a 5.56 suppressor on barrels less than 10" due to blast shield erosion but that anything over 10" is fine as long as the bore is coaxial to the suppressor mount.

The ballistics really aren't bad. I don't have my actual reloading data at hand but a couple of quick runs in QuickLOAD show, for M193: (QL calibrated to my known handload in a 20" barrel)

• 20" 3102 fps
• 16" 2934 fps
• 14.5" 2856 fps
• 10.5" 2578 fps

For M855 (Note my data for M855 are NOT calibrated):

• 20" 3077 fps
• 16" 2926 fps
• 14.5" 2856 fps
• 10.5" 2604 fps

So you see there is significant loss of muzzle velocity. It will be loud too: muzzle pressure for M193 in the 20" will be about 8500 psig. In the 10.5" barrel it will be about 16000 psig. That's going to be significantly louder. Although, my AAC can still brings it down to almost naked-ear levels--it's a little quieter on my 16" barrelled FNC.

[P-11 shooter]

Nothing more to add.


Just wondering if I was the only one thinking up "11 inch" jokes in my head.

[Shawn.L]

Nothing more to add.


Just wondering if I was the only one thinking up "11 inch" jokes in my head.

yes, you are the only one here that is always thinking about huge cocks

[RaisedByWolves]

With that short of a barrel I would look into the heaviest projectile you could find. The heavier round will leave the muzzle slower, but the gasses will also have more time to act upon its mass and you will wind up with more muzzle energy than with a lighter load in the same length barrel.



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[Guns4Fun]

I have an 11.5" barreled colt le6933.

From my limited research, with the 1/7 twist barrel, use 75g hornady tap (5.56) not .223 and you should get reliable fragmentation out to about 80 yards. Which in my opinion is far enough for my needs.

Also, i can gong steal plates with 75g PP ammo at 200yds all day long with it. A short barrel will still hit fine at distance, however, you loose fragmentation because of the slower velocity. I still wouldn't want to get hit with it even at 200yards.

EDIT---here is the bullet path chart info that i used.

If you zero both the pp and tap 5.56 at 50yards, the tap is 1" high at 100yds and the pp is .75" high. At 200 yards the tap is 1.2" low and the pp is 3" low.

[ithinkimamedic]

KAOS, Carcass and Guns4fun have summed it up well IMO, can't really and much more to it other than I almost prefer it to my regular AR's now.

I'll bring mine with me to the GS next weekend, your welcome to shoot it all you want. I have a sully stock and AAC hydraulic buffer in it (since I shoot 9mm out of it too).