The moment Jacob pulled the trigger, without the holder or barrel, he endured the full force behind the titan sniper in his current state.
The moment the bullet left the prime barrel, Jacob's entire arm shattered, but just in the nick of time, he managed to stow the gun away into the infinity pendant before his entire arm tore off and the shock wave killed him.
As for what happened to the gun after storing it in the infinity pendant like this, he had two theories about it.
The first, it would remain the same as it was stored like everything else, and the next time he brought it out, it would appear the same, and he had to deal with the reaming recoil like a time stop.
Second, the infinity pendant could not stop time, and the recoil will still happen in the pendant space, which would destroy all the things stored in his storage space, which was completely fine with him, or the infinity pendant would fully suppress the recoil as if nothing happened.
