It's a cartridge for a platform. What other 6mms that fit in AR15s are factories offering?
JBM says that the ELD 108 has 1.3 MOA less drift at 600yds @ 2750fps MV than a Sierra 80 .224 at the same specs.
Looks useful to me. Not everyone wants to spend $$ & time buying custom dies and forming cases for the wildcats.
I'm not familiar with what makes it different from the 6 PPC, but the one AR I've seen in PPC was a jamming POS. But that was 15+ years ago.
