Re: 6.5 Grendel Mag?
When comparing my mags I found the feed lips on my GI surplus type mags to stick out quite a bit more than the ones on my C-products grendel mags. I can load the grendel ammo in the 5.56 mags just fine though.
Comparing C-products 5.56 mags to the grendel mags there is basically no dicernable difference between the two except for the follower. The feedlips are ever so slightly larger on the 5.56 mags but I don't think it would affect operation.
I have not, as of yet, tried to use my 5.56 mags to feed my grendel. I just got my grendel upper a few weeks ago and have been either too busy or its been below zero, to go try it out. However, I don't see any reason that it wouldn't work.