The .223 and 5.56 is a fairly high pressure round, which makes it an effective and efficient round ballistically speaking, but it can get to be annoying to shooters and people near shooters... especially with high round counts.
Here are some devices which help direct concussion or sound downrange, away from shooters
Simplistic Shooting Solutions QD Brake Shields for AAC Muzzle Devices
Designed to fit onto AAC muzzle devices with the 18T and 51T standard, this tough steel shield is held in place by a single set screw. It redirects the muzzle blast from firing away from the shooter, reducing discomfort to the shooter and people to the sides and behind the shooter.
Simplistic Shooting Solutions QD Brake Shields for YHM Muzzle Devices
The QD Brake Shield was first conceived for the YHM family of muzzle devices and sound suppressors. Screws right on and uses the YHM mounting interface perfectly. This simple device redirects concussion and blast from the muzzle.
Griffin Armament QD Blast Shield
The QD Blast Shield from Griffin Armament is similar to the QD brake shield, but fits any muzzle device that is similar to the A2 flash hider. It fits all of Griffin's muzzle devices as well!
The Noveske KX5 is technically a flash hider, but it also does an excellent job of directing blast away from the shooter. A fantastic device for carbines and SBRs alike
Primary Weapon Systems CQB 556
Designed to tame the blast found on the 7.5" "Diablo" series of ultra short SBRs, this muzzle device greatly reduces flash and concussion on short, and standard length barrels alike!
Black River Tactical Covert Comp -- 5.56
A2 dimensions, Gemtech HALO compatibility, reduced weight, flash reduction, and reduced muzzle climb all in 2" and 2.2 ounces.