- Joined
- Jun 9, 2016
the M1 Rifle is intended to fire 150gr M1 or M2 ball ammunition (and similar) at or under 50,000 CUP (about 60,000 PSI). if your rifle is in good condition with original parts that are not warped or something, then you can shoot just about any commercial ammo on the market that isn't heavier than 165gr at faster than 2850 f/s on a hot day.I would still prefer having something I can tune to the ammo I'm using (which is preferably the cheapest I can find). I inherited this rifle and I'd prefer to have something that doesn't still allow damage to the gun, even if it costs more, than something that does, but is cheaper.
the key factors for damage are a weak or too-short action spring (20" length when new is typical, minimum 19" and maximum 20-1/2", with one end tapered, no coils stretched more than 1/8" or compressed more than 1/32"), improper or inadequate lubrication (use a white lithium grease, lubriplate being the actual still manufactured correct grease, and apply as per the M1 field manual), or an op rod that is out of spec (it has a very long straight cylinderical section that must not be bent).
if the rest of the rifle is in good order, you can shoot your cheap ammo as you please.
that being said, the adjustable "plug" (really the gas cylinder lock screw) is outdated in favor of the self-adjusting ported screw that function based on the M60 design, where it allows pressure to build up to enough to work the operating rod before venting the remaining gas via a port that relieves pressure. both of these are the "easy answer" to peace of mind.
edit: oops seems like someone posted some vids already. it's probably been done before.
Last edited: