Re: Badger Ordnance EFR
The through hole of the EFR is right around 1.2" The MTU will be too large to work correctly with the EFR and have any clearance. You could shave the O.D. of the barrel to 1.075" starting about 1/4" behind the EFR and let the straight profile run forward until it intersects the original taper. I don't like or recommend altering barrel contours once the blank maker is done but you could do it.
I like to have at least 0.050" clearance around all sides.