Firing pin seems to stick.

[J. A. EARLY]

Brian,

I had the same problem on a 16 Trojan. Shooting cheap factory stuff, no problem. Shooting my reloads, problems.

Quite a difference in primers, their hardness and material, and depth the pins would drive into primer. Also a difference in head sizes of resized spent hulls. There were no internal problems with gun but when I shot both barrels, thought I would break the gun getting it to open.

Change shells and see if it does not go away.

[Bill Murphy]

Yup, change shells or change primers. Primer problems are common today, in both bulk primers for reloaders and in factory shells. Just change your source.