I replaced the 15x1 Surefire Flash Hider with a 15x1 to 5/8x24 thread adapter from Griffin Armament and added Surefire 7.62 Socom Muzzle Brake. With such a short barrel, I prefer a brake to act as a sacrificial baffle to protect the suppressor. The thread adapter adds roughly 3/4" to the barrel. I also replaced the wobbly MP5 handguard with an HK53 length handguard from HKParts.net. It's long enough to fill in the gap at the barrel trunnion and has much less slop.