Here is what I am encountering, I did a search and found the following which is about the same as my problem BUT the thread didn't mention what the resolution to the problem was. I will make my own repair, I just need to know what to buy first, I'm not looking to ship the gun to a repair facility.
My A5 light 12 has been jamming up, the shell in the chamber fires and ejects, second round feeds to the carrier and doesn't make it quite high enough to get into the chamber. It just locks itself up between the carrier and the receiver just underneath the barrel.
Another time this happens is if i use the "auto-load" feature. Empty chamber with the action pulled back; insert shell into magazine tube; let it go; shell springs onto carrier, carrier lifts half way, shell pinches onto reciever; everything locks up.
Something else interesting is if you are holding the bolt and push the release button and ease the bolt forward gently, it will hang up just as the carrier begins to lift & the carrier has to be pushed upwards or push the operating handle forward to close. This won't happen if you just push the button without holding the bolt, then it will slam home as it should.
I have looked at the field service manual under troubleshooting but I still need some input from the field.