meketrefe
.450/400 Nitro Ex
I mean there are plenty of big bore options, or even the AR 10...
Also this isnt a mass produce shoe. It's like 1 dude and his shop. Or for those still shooting 3 gun, lot of 3 gun ARs with comps (granted porting wont be anything like a 3 or 5 chamber comp)
Do they gave any close up pictures? How is it done?