#50997
Whirlibird
Whirlibird
Survivalist
member10

The FP ‘tube’ has zero to do with bolt timing.
If the carrier is improperly drilled, it can effect FP depth of penetration. But that’s not a timing issue with in spec parts.

What can effect lockup timing is the can pin hole locations (and angles) both in bolt and the carrier. A properly timed BCG is rotating into lockup as the FP is just beginning to be able to move forward enough to move past the breech face. Hence the FP dimple, not enough energy to pop the primer but still marks it.

As long as the parts are within spec, you should be good, FA or SA.

The other difference in some SA carriers is the relief cut that exposes the FP ring. This only matters if your hammer follows the BCG home, meaning you have a screwed up FCG.