Tell me what I'm overlooking.
New 13.7 upper, mid-length gas, .223 Wylde chamber. Did not measure gas port size, another user reports .0735, though.
Ammo is my range 55gr .223. Everything I use runs on this ammo, I've filled nearly two five gallon buckets with brass, I'm not changing, it is what it is.
Lower has an A5 extension, the upper I took of the lower was 16 in, carbine gas, and ran smooth as butter with an A5H3.
Without going into a lot of detail on how and why, I used the bolt from the upper I stripped to get the rail I used on this build.
Head to the range. Fire one, cycles, fails to feed - bolt closes on empty chamber. Ejection straight out at 3:00, not as far as I'm used to though. Practice my immediate action a couple more rounds, and use a couple mags just in case, before I decide to put in a new buffer - only problem is that I only have carbine buffers in my range bag.
Head home and turn the A5H3 into an A5H2, and an A5H0 into an A5H1. Run back to range. Same deal with both buffers, although I did manage to get one case length-wise on the bolt and the edge of the ejection port. Head home again.
At home I decide, WTF, even though the brass looks good, maybe I ought to check head space, since, you know I spent all that money on gages. Of course I have to clean the bolt and bolt carrier, which may not have been a bad idea, head space is okay. Convert A5 buffers back to H0 and H3, grab another rifle with a carbine lower, and head to the range.
At the range with the A5HO in the rifle, same deal, brass is falling at 4:00, I'm getting tired of push/pull, cycle, and have determined that the new BCM upper really doesn't make much difference for left handed operation.
Time for a change, I take the bolt from the rifle I've been using and put it in the other rifle. Works fine. So I take the carbine lower off the other rifle and put it on the 13.7. Since I'm a glutton for punishment, I started with an H3, then an H2, and then a Carbine buffer. Same deal.
Finally, it was getting dark, so I put the rifles back into their original configurations, and decided to try the A5H3. Fired a mag at a pretty good clip, didn't lock back. Fired what was left of another mag, didn't lock back. Brass is pretty much in a pile at about 4:30.
I'm missing something obvious here, what is going on?
ETA: Gas block is a pinned Geissele Carbon Steel Gas Block.
Last edited by 26 Inf; 01-10-20 at 02:37.
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Originally Posted by Clint
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