Grendel vie six8 recivers

[A5BLASTER]

This seems like a way to get some extra overall length to run some heavy bullets at pretty decent speeds?

Cpd metal grendel mags allow 2.295 coal length. The SIX8 pmags only allow 2.300 coal.

Unless you window it then it would allow longer. I windowed a six8 pmag and I can run loads from the mag at a length of 2.360 comfortably. My chamber doesn't allow that length, just the windowed mag will allow that. Would need a custom throated chamber to use that kind of length.