.22 cylinder ID help?

by Andrew , Bloomington, IN, Sunday, August 18, 2013, 20:09 (4059 days ago)

I came across some cylinders in my travels today, and these 4 are eluding my smarts.

The 3 on the right are identical, except one has an "M" stamped on the face. They aren't Ruger, just a tiny bit longer and the star is a bit smaller. The one on the left is unfluted, marked .22 WMRF, and has a tiny star.