What was the problem with the ARC mags? I have a Xylo and Nuke Gen 2 where the mags seat, but sit too low for bolt to strip the round from mag.
Do a search... ARC has had more issues than most.
Just the fact that your Nuke is a Gen 2 should tell you something.
Plus, just go to any match, there will be dozens of MPAs, Manners', MDTs, KRGs... and maybe 2-3 Xylos. Yeah, it could just be a popularity thing, but if they were all that and a bag of chips you'd see more than a few of them I'd think, they've been out for more than a few years now.
Don't get it twisted, I think Ted's stuff is brilliant and have almost pulled the trigger on more than a few of their things, but with their track record and how expensive this shit can get, IDK... being an early adopter can be rough.