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1/7/2016 9:34:53 PM EDT
Back Story:

So I made a trade with a forum member to switch out my .308 Maten from a UBR stock to a PRS. We did a full system switch and everything looked normal. Stock was basically new and looked like the rifle buffer and spring were new as well. Wasn't able to get out to the range for about a month since work has been crazy but finally made it out the other day.

Issue:

I charged the handle and the bcg was acting like it wasn't heavy enough to strip the round off the magazine. It would get halfway up the round and jam it between the bottom of the bcg and the top of the mag. I'd drop the magazine and cycle the charging handle to extract the round then start over. Usually the second round would chamber and I could fire the rest of the mag without issue. First round would have the issue every time with different amounts of loads, different mags etc. Additionally, the bcg wouldn't lock back on the last round of every mag. It looked to me that the bcg wasn't cycling as far back as normal but I couldn't tell for sure. If I pulled the charging handle back as far as I could and manually engaged the bolt catch, it would hold it in place like normal.
1/7/2016 9:35:34 PM EDT
[#1]
Potential Diagnosis:

I immediately thought it was the bolt release. The screw on my Maten lower likes to walk itself out and it was protruding some. I figured that must be the issue and since I didn't have an allen wrench on me, bagged the gun and took out my frustration with a shotgun on some paper terrorists. Once I got home and tightened the screw I began function checking the rifle and realized that the bcg would lock back on an empty mag if I pulled the charging handle back but it was catching on the follower and not the bolt catch. Curious. I pulled off the lower and checked things out. Everything looked normal. After thinking about it for a minute and realizing that the only thing that has changed in the rifle was the stock assembly, I removed the buffer and spring. HERE IS MY ISSUE. After measuring the buffer, I realized I had been sent a STANDARD AR15 rifle buffer and not the AR10 rifle buffer I needed. Apparently the AR10 rifle buffer is shorter to accommodate the longer bcg and heavier to cycle the bcg correctly. A new buffer and spring are on the way! Hopefully all will be well.

Thought I would post this in case anybody was wondering what would happen if you ran a standard ar15 buffer and spring instead of the correct ones AND if you make that mistake, here are some of the symptoms to help diagnose your issue!
1/7/2016 9:54:35 PM EDT
[#2]
lol yes the 308 buffer system is quite different than the 556.
1/7/2016 10:00:34 PM EDT
[#3]
Haha yeah found that out the hard way. Thought thats what I got in the trade. Probably an honest mistake!
1/7/2016 11:18:26 PM EDT
[#4]
Quote History
Quoted:
Haha yeah found that out the hard way. Thought thats what I got in the trade. Probably an honest mistake!
View Quote


Man you're nice. I'd assume the guy screwed me on purpose.
1/9/2016 12:02:34 AM EDT
[#5]
I try to assume the best when in doubt. People make mistakes and I'm not immune to it myself. I just hope if/when it happens to me that person gives me a chance to make it right!
1/9/2016 12:04:19 PM EDT
[#6]
This is one of the most common mistakes in the AR10/.308 frame sets.

There are "builders" out there that crank abortions out like this with no test-fire, thinking it's cool and that they are savvy.

We see it all the time here.
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