I have a AAC M4-2000 suppressor on it's way to me and I've decided to do a SBR upper for it.

Question:  How short can I go on the barrel without totally ruining the accuracy of the .223rem round?  I intend this to be a plinker, not a target rifle.  I'll be shooting distances well under 50 yards.

Any suggestions?  Better yet, any HARD facts about the minimum length?

I normally shoot PMC FMJ rounds.. and will be experimenting with surplus rounds.  I hope to be reloading .223rems soon, and will make some sub-sonic loads, too.

Thanks in advance!

Accuracy does not suffer with a shortend barrel length, although,velocity drops, which decreases leathality and range. Read the Ammp Oracal, you can find a link to it at the top of the ammo forum.

Under 10.5" and you may have problems with baffle strikes...  

Strictly speaking, shorter barrels are more accurate than longer ones.

Realistically speaking, a bullet obtains it's maximum velocity at a given barrel length (depends on the cartridge). Once the bullet has obtained it's maximum velocity, the bullet starts to slowly lose stability. While the firearms accuracy is dependent on the velocity of the bullet, it is also dependent on it's stability, which in turn is dependent on the length of the barrel.

Sammy

Quoted: Strictly speaking, shorter barrels are more accurate than longer ones.

My OA93 pistol (6.5" barrel) is very accurate. More than any pistol I have shoot or seen.

Quoted: I have a AAC M4-2000 suppressor on it's way to me and I've decided to do a SBR upper for it. Question:  How short can I go on the barrel without totally ruining the accuracy of the .223rem round?  I intend this to be a plinker, not a target rifle.  I'll be shooting distances well under 50 yards.

I use a Bushmaster 11.5" barrel (1-7" twist) with an M4-2000.  At 100 yards and less it is just as accurate as my 16" rifles during general target practice.  You will not notice any degradation of accuracy shooting at 50 yards with most any quality manufactured barrel.

The Azalin

I have shot 1 1/4 - 1 1/2" at 100yd with both my 7.5" and 11.5" with 52gr Hornady HP off sand bags and with a cheap 3-9x40 scope.

I've used my 7.5" with WARRIOR from in-laws tree condo and busted fox squirrels with ease at 65-80 yd.