AR Sponsor
Posted: 3/23/2009 6:43:05 PM EDT
My friend bought a Blackthorne kit. Yes, I know, but he couldn't afford to get an AR any other way!
We did some shooting this weekend and his rifle started short stroking really bad. Basically it turned into a single shot. It was barely ejecting the rounds with them landing a few feet away. At first I thought the mag was sticking, but it was clear after a couple more shots that the mag was not the issue at all. I popped the BCG out of my RRA and told him to try it. As soon as he handed me the bolt I noticed the carrier key was loose as hell! It was definitely not staked correctly. His AR ran like a top for the rest of the day. When we got back to the shop, we tightened the screws to 40 inch pounds and staked the hell out of it with a cold chisel we ground special for the job. When we tightened the screws it was obvious that they were torqued to less than 35 inch pounds as even at this torque the marks were not aligned. The screw clearly passed the original marks at 35. We learned the easy way that the staking on the carrier key is as critical as everyone has stated. The torque of the screws is also important for the proper amount of stress on the screw so it stays tight. There does seem to be some debate about how much stake is proper. My RRA bolts have done fine for thousands of rounds so far. I will be checking the carrier keys more often and buying some more of the screws because they could break someday. I just thought that telling what happened would help someone identify the symptoms easier. |
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