I have an older (series 184 serial) Mini 14. I put a new Hogue synthetic stock on. About every 3rd or 4th shot, the trigger housing assembly falls out. Suggestions ......... and I have carefully "snapped" the trigger guard into the seated position.

I had this happen to one I owned. How I fixed it was I had a gunsmith re-bend the trigger guard so it locked tighter. I also got a new stock and the problem went away. I wasn't sure whether it was the stock being to loose and allowing movement or if it was the trigger not locking up tight enough. I know it popped out when the hammer was pushed back to the down position by the bolt. The force would pop it loose.

Thanks Bob

Did you use the stock reinforcement plate? Most stocks do not come with them. I'm not sure if not having it would cause that problem, but it was the first thing that came to mind.