Frank, I think the 140 ELD M should be a great bullet, but getting exits might be a tall order to depend on from it. Fully broadside bucks, probably, but outside of that I would think it's probably not as likely. Although at Grendel speed it'll hold together great, it could make a heckuva front end expansion that limits it popping out. This is all a guess since I have only really used the 147 at 6.5 CM speeds.
Looking forward to seeing how your 6.5 turns out. The SS ones have been tempting.
