Originally Posted by Jim Duncan
My 30.30 fire formed brass measures 1.495 headspace. My resized brass measures 1.470 headspace. My factory ammo before firing measures 1.470 headspace. Isn't this quite a spread? Anybody out there have some input on this?
Umm, the REAL problem is that you don't know what headspace is.
Headspace is the distance between what stops the cartridge from moving forward and what keeps it from moving backwards. In the case of a rimmed, or belted, case it's the thickness of the rim. Period, end of discussion.
Chambers have positive HS, cartridges have negative HS. For most cartridges, the chamber is datum to datum +.007, the cartridge is datum -.001 to datum -.008 or a allowed clearance of .001 to .015.
You can, if you desire, shorten up the amount of shoulder setback, but lever guns don't have the camming force to seat a round that's slightly oversize (unlike a bolt gun), so expect to find yourself with the occasional round jammed in the chamber.