muzzle device is the key, if you're concerned about blast from shorties. the muzzle device makes all the difference. you'll need to be careful about selecting one that's california legal, obviously. the problem with california-legal compensators is that compensators/brakes often tend to be the blastier devices.
check out the battle-comp...
www.battlecomp.com.. it's cali legal, made in cali, and is an excellent comp, but brings flash and blast down to very similar to an A2 (which is not cali-legal, for stupid reason).