Failure to feed

[ARMYEOD]

Yes I have read other posts on this issue. Caveat: I have had two other Grendels with NO feeding issues and using same E-lander mags.

Problem: Failure to feed second and subsequent rounds:

Situation: New Grendel Hunter upper with their BCG. (I have had two other Grendel Hunter uppers, both amazing)
New BCM Lower complete.
E-lander mag
Tried three different loads: Hornady Black 123, Wolf Steel Case 100 grain and my hand loads. All of these rounds worked fine in other Grendel builds.

So. Is it the mag? Or possibly need different buffer/spring setup???

The mag fits loose in the magwell but lock in OK.

I have to pull the charging handle and release for my second and subsequent shots.

I am suspecting the mags. Will try some others.

[NebSig]

Personally - When the magazines work in 1 firearm and not another I start to think its the new item introduced - this case the new lower. Seems like mag seating issues could be out of spec lower tolerances - though typically I haven't heard of that with BCM.

Try the upper on the other lowers? Might help narrow down if it is an upper or lower issue. Alternatively, try the other uppers on this lower? By process of elimination, you could find the culprit to be one element rather than all of the new firearm being suspect.

All of my various magazines (E-Lander, ASC, Duramag, C-Products, Amend2, Uni-Mag - disclaimer I honestly do not recall exactly which all are different and may be listing one twice between manufacturer/product name) fit my particular lower about the same, with very very little difference in fit/feel and slop. Though I think the Amend2 are slightly tighter fit than the others - polymer/bulge issues.

[ARMYEOD]

Problem solved. It was the mag. Used other magazines and it is GTG.

Incidentally, shooting the Wolf WPA 100 grain steel cased rounds I am getting insanely good groups. Works for me. I just bought a case of 500 more.