[Jeff Higgins]

Especially true with the old Garand, Paul. Many modern, slow burning powders commonly used in the .30-'06 raise gas port pressures above what the Garand is designed to take. G.I. loads use powders in the 4895 to 4064 range, which are considered relatively "fast" powders (when used in the .30-'06) by today's standards. Many modern loads use much slower powders, such as 4350, 4831, RL22, (or their canister grade equivelents) and even slower. These will batter the gas piston if used in excess. A few rounds won't hurt, but a continued diet will.