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I've already spent a good amount of time looking this up online. Have come away with a mountain of "things to consider" to see which ones might fix the issue. Thought I would also ask here:
With a PSA 18" barrel upper, and a rifle length gas tube. I was experiencing failure to eject, and short stroking issues round after round. It did it with multiple Pmag magazines and also the D60 drum. It was failing to extract from the chamber.
I realized that the BCG which I had heavily lubed (who knows how long ago) had gotten pretty sticky, even into the firing pin channel, I removed all the lube and tried again. After that it was extracting but not loading the next round. After going through a mag like that, I was able to get it to go through another mag without having failures, but when I tried the D60 again it would have failures to feed. I tested the mags I used the same ammo with a 10.5 inch pistol upper and all the mags, including the D60 worked without a hitch which led me to believe it wasn't the mags or ammo and was more related to a gas issue.
Online research said it could be anything:
- too small gas port in the barrel
- tolerance stacking - try a different BCG
- misaligned gas block and gas port
- some type of metal shaving obstructing the gas port or tube.
- lower buffer weight needed, or lighter spring
I was using a carbine lower. I've had really positive experience with other PSA 18" rifle length uppers. If others have experienced similar issues, what did you identify to be the problem?
I can definitely use deductive tests to try to narrow this down further, I was hopeful after what I already did try with it that it was cycling well through 1 mag, but definitely don't trust it enough for it to be anything but a range tester until I can do more testing with it. I'm happy to offer it to the minds here for what they hypothesize.
Edit to add: I need to put a lot more rounds through it, but I found with the D60, it would fail to feed when the D60 was full, but after limping through half the mag, it would load the next ones. The D60 did not have this problem with the 10.5 pistol.
With a PSA 18" barrel upper, and a rifle length gas tube. I was experiencing failure to eject, and short stroking issues round after round. It did it with multiple Pmag magazines and also the D60 drum. It was failing to extract from the chamber.
I realized that the BCG which I had heavily lubed (who knows how long ago) had gotten pretty sticky, even into the firing pin channel, I removed all the lube and tried again. After that it was extracting but not loading the next round. After going through a mag like that, I was able to get it to go through another mag without having failures, but when I tried the D60 again it would have failures to feed. I tested the mags I used the same ammo with a 10.5 inch pistol upper and all the mags, including the D60 worked without a hitch which led me to believe it wasn't the mags or ammo and was more related to a gas issue.
Online research said it could be anything:
- too small gas port in the barrel
- tolerance stacking - try a different BCG
- misaligned gas block and gas port
- some type of metal shaving obstructing the gas port or tube.
- lower buffer weight needed, or lighter spring
I was using a carbine lower. I've had really positive experience with other PSA 18" rifle length uppers. If others have experienced similar issues, what did you identify to be the problem?
I can definitely use deductive tests to try to narrow this down further, I was hopeful after what I already did try with it that it was cycling well through 1 mag, but definitely don't trust it enough for it to be anything but a range tester until I can do more testing with it. I'm happy to offer it to the minds here for what they hypothesize.
Edit to add: I need to put a lot more rounds through it, but I found with the D60, it would fail to feed when the D60 was full, but after limping through half the mag, it would load the next ones. The D60 did not have this problem with the 10.5 pistol.