Originally Posted by
lengthofpull
I was finally able to do some more testing. The plot thickens.
1. I thoroughly cleaned my barrel/chamber/BCG and lubed up with slip2000.
2. I put 20 rounds of Federal XM193 into a 30 round Lancer mag and shot it without issue. I put 20 rounds of Black Hills 77SMKs into a 20 round Gen3 pmag. In 8 rounds I had 6 rounds that fired and cycled properly, and 2 malfunctions. They were failure to feed, the fresh rounds would get stuck where the back half of the cartridge was in the mag and the other half is on its way up the feed ramps. At this point I realized I was out of time and had to stop shooting.
3. I went shooting again (no cleaning after last time) and experienced the following:
•20 round gen2 pmag loaded with 75gr Hornady TAP fired 20 rounds with 2 failures to feed
•30 round Lancer mag with Black Hills 77s fed 3 rounds properly and then had failures to feed (top round in mag undisturbed), failure to eject (spent shell stuck in ejection port) and even 1 failure to extract.
•30 round gen3 pmag with XM193 would then start frequently failing to extract spent shells and locking the gun up tight. I had to mortar the gun a bit to get the spent shells out. This happened maybe 10 times with one mag.
4. At this point I wanted to start ruling things out. Swapped the lower with another known good lower, also with rifle buffer system. Issue persisted. Swapped lower with known good lower with Vitor A5 recoil system. Issue persisted. Swapped BCM BCG with known good BCM BCG. Issues persisted.
Anything else to check at this point before I take it to a smith?
Thanks,
-LOP