Odd 9mm chamber
 

I recently acquired a 1936 S/42 with a strange chamber. About 3/4 of the way into the chamber there is a small "ridge" of metal that is a little smaller in diameter than the rest of the chamber. It seems to amount to about 1/4 the length of the chamber. Cartridges feed and chamber correctly but the fired brass shows a very slight shoulder where that ridge is. It irons out fine when I run the case into a sizing die but I've never seen a chamber like this. Almost like a larger diameter reamer was run about 3/4 of the way in then stopped.

Any ideas?

Believe this is just the stepped chamber that is normal. Bill

Confirmed. The stepped chamber is standard according to the blueprints. If you want a copy of the blueprints, see the FOR SALE forum. The information is in a sticky post near the top. (YES a shameless plug for the blueprint CD! :) )

Huh, I never would have thunk it. Learn something everyday. I guess I won't cut it straight now.

I just looked into the chambers of my 1908 1st Issue military and my other 1936 S/42. Both have remnants of the stepped chamber but they look to have been reamed a little to eliminate the step.

My 1917 Artillery had a distinct step. Where in SC, Jim?

Within 10 miles of you. North of Chapin.

JimD; I suspect more from use than reamed. Bill