Im a big fan of full length barrels on AR's, but lately ive been itching for an M4gery.  Ive had a 16in upper in the past and it was loud as hell, too much for my tastes.  someone recomended taking the muzzle break off.

Question:
What is the least noisy option for a 16in upper(barring a silencer).  Are any muzzle breaks quieter than just a plain barrel ?

Probably not the answer you want to hear, but no muzzle brake is going to be any more quiet than a plain barrel.  A brake may redirect some of the gas so it doesn't seem as loud to you, but it's still there.  Any noticable reduction in sound, however slight, is enough for BATF to rule the brake is not really a brake, but a supressor and thus subject to the NFA.  If you recall the original flash hider/brake on the Vietnam era XM177 was ruled to be a supressor even though it only reduced sound by 1-2 dB.

My M4 isn't that much louder than my 20" AR.  Both are just plain barrels.  I will be sending to KKF to get a muzzle break sometime as I want the reduced recoil on the M4.
Bill3508

I don't know the answer to your question, but my 20" AR "seems" alot louder than my Ruger Ranch Rifle when firing the same ammo.
I believe this is due to the muzzle brake on the AR. The Ruger has a plain barrel and may be just as loud, or more so, but not from behind the rifle.