this 11.5" pistol that I first built in 2006 is now having feeding trouble with polymer Wolf, and It was not a problem until recently. I think the problem is in the upper group somewhere.
Specs:
Barrel: JSE surplus special, 11.5" with pinned FSB, 556 chamber, 1/9 twist, non-chromed. I think it is a Shaw or Wilson barrel from long ago
Brake: Levang
Generic upper reciever, non M4 ramps to match the barrel
milspec gas tube
generic bolt carrier group
SIG brace pistol kit
Carbine buffer and spring
I'ts seen various configurations over the
years, but the barrel, brake, lower, and BCG have been common throughout. And it ran like to top with Wolf until recently. the Sig Brace and flat top upper are the newest additions.
Problem: it short strokes on poly-steel Wolf, but runs fine on brass cased Wolf Gold and my brass cased reloads. Sometimes the bolt closes on an empty chamber, sometimes it fails to eject the spent case and I get a double feed jam.
I think its a gas issue. Here's what I've done so far:
changed mags
Replaced the gas rings
replaced the gas tube
tested the upper on different lowers, edit: the problem persisted
replaced buffer spring
replaced buffer
Next to try?
new bolt carrier/gas key?
punch out the FSB pins, remove it, and check that the gas port is not plugged?
What have I missed?