bolt action/semi auto
 

I've watched several military specials on sniper rifles and such, and they keep discussing how bolt action rifles are inherently more accurate than semi auto rifles. I guess I just don't understand why. All things remaining the same, it doesn't make sense to me why with 2 rifles the bolt action is more accurate than the semi auto. There has to be something more to it than just the action of the gun.

More moving parts, more parts moving during firing. This affects the mechanical accuracy and the level of technique required to shoot each to its potential.