Rossi youth .243 issue

I took my son's Rossi .243 out to the range. I shot some reloads in it. Everytime after the shot with the reloads, the gun breeched open. Does anyone know if it is due to the bullet not being seated down enough and allowing the locking mechanism pop open after the shot? Any help would be appreciated.

I have a Rossi .223 and never had any issues. Does it have the same problem with factory loads? If so I'd sure send it in or call Rossi. Good luck.

Didn't do it with factory loads. However, I don't have any more factory loads to try. Guess I need to go buy some.

Most of the Rossi problems occur with the .243, no matter what load you use.

However, the .223 Rossi's generally have not had the problems!