I bought a No. 3 action to build a dedicated lead bullet bench rifle. With it came a Moulds hammer and a T.L. Moyers adjustable trigger. I fitted a Ron Smith gain twist barrel in .321 caliber and cobbled up a stock and forearm so I can test fire the rifle. The bullets are breech seated. Here is...
Years ago I saw plans on how to make a SKS full auto. As I recall all it took was a shim made from a piece of tin can placed somewhere in the trigger group. I would suspect the problem to be in that area.