Went to the range the other day and took my AR10 308 with ladders for the 155 TMK , 165 SST’s, 168 SMK’s, 178 Hornady Match HPBT’s and 225 gr Match HPBT’s. Ran through them in the above order when I was running the 178 gr ladder I loaded it up low to high RL 17 2.83 COAL. I was finishing ladder the first portion of ladder and I ran 47.5 through 49.5 gr loads instead of the 44 through 47, it ran 2,817 FPS at 49.5. The only thing that showed was a little faint smile so that was max. So I said what the hell run the 44 gr through 46.5 portion of the ladder last and record speeds. At 46.5 the round went through No concerns except I looked at the case and the primer was gone. Oops. I said to myself I should pull last round. Bad news the last round did not go totally into battery, and the bolt was locked with the live round in chamber. Tried motoring rifle, no joy tried placing a rod down chamber and pushing round out. No joy. So my day with the 308 was done and I was going to do the 225 gr ladder. not today!! On the way home tried to think how the rifle action was stuck. I rationalized that since the primmer was blown it bounced of boot face at the return stroke of the bolt and bounced it into the chamber. That way when the last round tried to push down to battery it jammed the round at the shoulder of the chamber catching the bolt with pressure on it just as it tried to twist and lock and the bottom of the bolt’s cycle. I got home and thought my only chance to dislodge it was to remove the free float barrel and the remove the barrel nut. I new the bolt would still have it jammed but loosening would alllow me to get a small amount of deflection of the ramps from the bolt which if moved back and forth enough might release the bolt from the ramps. Upper in vice I manipulated the barrel with back and forth pressure while placing a vice grip on the end of the bolt. After working off it trying to push the bolt back and forth while manipulating the barrel the bolt finally let loose bring out the live round with it.
amazing it turned out to be lodged just as I had thought. The speed recorder was 2,436 FPS on the round while I had run up to 49.5 gr RL17 with no issue and at 2,817. So go figure blew primer 3 gr less than max at 49.5. gr. Got me puzzled. I have also read repeatedly about RL17 being slow enough that there is no way to get enough RL17 into a cartridge to get it to overpressure with people running extremely compressed load with 200 gr bullets no issues. All brass was brand new Winchester 308. All brass was fully resized wit win large primers. Could have been a loose pocket or is it more likely that I could have placed primer improperly. Who knows but it could have been a very expensive. Luckily everything cleaned up and functioned properly. I had a bore scope and the chamber seams fine so I am good to go. Just extremely puzzled. Any thoughts
