i took my mini 14 to the range yesterday. after around 15 rounds i pulled the trigger and there was no shot. i check the chamber and found no bullet in there so i had to recock it . then it got worse then it bolt jammed betweem the recieverand it took me a while to get it loose again and after that i could only get thru around 3-4 shots b4 i had to recock it again. what part do i need to replace or whats wrong with it.