I am using 124 gr MG with 10.4 of N105, CCI small rifle primers, 1.225 OAL. Make 171-173 PF at about 1380-1400FPS. Very soft and minimal dot movement. The dot doesn't leave the glass
Do you know what internals it has. Or any clue on how many rounds thru it. Is there a chance you could talk to the builder since he is local to find out more info on it