Sorry to hear you may have the same problem.

A caliper is definitely a good tool to have, for multiple jobs. You can do some things well with it & others not as good. You can get in the ballpark for throat/chamber measurements with one but I finally broken down & bought a pin gage set to do such items, which is the way to go. A set just made better sense, for me, than buying a couple individual pin gages, & I'm glad I did. The chambers, for example, have a tapered cut, even though it's a "straight case" & the pin gages will allow you to see that better, though my gun's were obviously not uniformly tapered. The 657-5 chamber openings (case head) measured .447" & the opposite end (case mouth) measured .440" while my 357NG has .438" & .437" respectively. Here's a related post: Plug Gauges you can afford...

As for spec/limits I used those from the "SAAMI Ammunition Specs & Standards pdf you can download from their site. Attached is the 41 Mag drawing with specs/limits.