no bolt action amounts to a damn in combat,and they have not done so since the advent of the Garand, nearly 65 years ago. Contrary to what a lot of bsers claim, lots of the sniper HITS are will within the 600m capability of a good AR-15. Military snipers also miss a lot, and dont have any real reason to care about it, either. They can miss half of their shots, and nobody is going to just stand around after the first shot fired at them. So the sniper is still denying the enemy free use of his AO, and he's still a valuable source of field intelligence, even if he never fires a shot.
You aint in the military, and if you are, you aint a sniper. The civilian survivalist is well advised to just forget about the bolt action. The bolt user can't risk firing at several guys who walk past him, at 25-50m. The auto user can often hit all 4-5 of them at such a range. The survivalist should never fire a shot that he doesn't HAVE to fire, and sniping is almost never a case of having to fire. It's a choice to fire. When you don't have a safe base to run to, don't have a spotter with M4 and grenade launcher, dont have a security man with a SAW watching your back, don't have a chopper on call for evac, dont have napalm strikes on call, etc, you'd better have rapidfire capability with your rifle, at the least, and a sound suppressor would be a real good idea, too.
