Have a BAR in .243 win. Was testing some loads and on the final round when the clip was empty the bolt went all the way back like it should to lock open,but it went beyond that point by 1/4 ".It jammed open and could not close.I had to take it completely down.There was no pressure showing on the brass,I'm not close to max. load.Has anyone any idea what would cause this,I have fired 300 rounds through this rifle since I bought it new,first time this happened.Any ideas or suggestions would be a help