I'm assuming that the bolts on the AC556 and Mini-14 are identical - but can anyone confirm this for me? Also, what's involved with fitting a new "used" bolt to an AC556? Should they drop in, or is fitting an issue? I don't need a new one, but would like to acquire a spare. But, before I plop down money on a spare bolt, I want to be reasonably sure that I can fit it to the receiver without too much difficulty.