Just gave it a try and so far, so good.
Drag is only present when the trigger is released.
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All my mags are labeled and numbered. Unfortunately, due to "the heat of the moment" during class I wasn't able to mark the mags that were used during the malfunctions except for two of them. I've since replaced the entire BCG with a tried and true BCM BCG (run in a different gun) and will retest this weekend.
Out of curiosity, what is a good powered off-the-shelf cartridge?
I've been running XM193 for the past five years, but have read of a few catostrophic incidents.
Hit the range with a friend and ran through 124 rounds and brought two of the known magazines that participated in this past weekend's five malfunctions.
Magazine 1 (OKAY Industries #1) consistently held the bolt open on the second to last round (i.e. round in chamber, one round left in magazine). I would then pull the magazine out and throw three to four more rounds in and attempt to shoot till bolt hold-open. My gun would consistently hold the bolt open with a single round left in the magazine.
Magazine 2 (Parsons #4) would nose dive a round near the end of the magazine (five to six rounds left) and was only able to do this once. This seems like a magazine issue and not a gun issue.
Looks like I narrowed down my problem to two bad mags. Bummer as they both have Magpul followers. Any way to remedy these issues?
Other than that, the gun ran flawlessly albeit a bit overgassed on the new BCM BCG which now has 169 rounds on it and nearly 1400 on the upper.
Save the magpul followers and toss the malfunctioning magazines. Not much you can do to save them suggest buy some more quality usgi mags or buy p-mags.
If you have to try to save them you could try new springs.
Hey, thanks folks.
I positively identified the problems as of last night.
Okay Industries #1: Worn feed lips. I bent them back a bit and now the gun runs flawlessly with this magazine.
Parsons #4: This magazine was running a Magpul Gen1 follower and the follower would sometimes bind near the upper 1/3 of the magazine. Upon closer inspection the culprit for this follower were the side ramps/tabs. I filed them down and the magazine will no longer nose dive ammunition and was tested today. My gun runs flawlessly with this magazine.
Problem solved.
Wolf, XM193, Fiocchi and PRVI M193 were all run through the mags and, voila - they work.
Glad to hear you got your issues resolved :)
Yup.
I didn't follow my own advice with regard to bringing untested equipment to class. The week prior to the SCT carbine classes I had installed Magpul followers in ALL of my magazines that did not already have them. Since I never had a problem with the Magpul followers till last weekend I ASSumed that all was good.
At least the instructors gave me a thumbs up on my primary/secondary transitions and malf-clearances.