Recently built a 300 BO upper. I loaded 3-4 shells at a time in an old 20 round mag. It fired two and jammed on the 3rd one several times. I was going to bring several mags to try. Just wondering if it is the magazine or my weapon. I think it is the magazine. What do you guys think. Got to go back. Oh, the loads were 125 gr. Nosler ballistic tips loaded to a grain below max. I only fired about 6 rounds, two three times. I went to the range at the last minute with a friend and grabbed my stuff. I have got to go back during the week when it is not so crowded.
