I just spent an hour and a half with two guns trying to measure head clearance with plastigage-actually with "SEALED POWER" strip from NAPA.
Using a bunch of fired FL sized cases, the plastigage smeared when the bolt was closed. The bolt turned relative to the case head, smearing the [plastigage. Widths varied with the smear, but there was no reading I'd believe.
I've read that some guys measure head clearance with plastigage. What am I doing wrong?
joe b.