Thanks. I appreciate that. I can't see anything on the lugs: no bumps, no cracks. I don't get it. I'm going to fire some factory 140-grain Core-Lokts and see what happens. I know the 175-grain RN loads I shot through it are ambling along at about 2300 fps using Ramshot Hunter - nothing even marginally hot - but the bolt wants to stick. From what I understand, M1909s are a little harder to cock than M70s or commercial M98s - and this is true of another M1909 I have that was built with a hardened and trued action - but this is significant. I'll see what the factory rounds do. So far it's a mystery.
Thanks again.