I spent a few minutes in Hall Sharon's shop back in 1975 - where they were button rifling blanks. The whole shop shoot under the strain of trying to 'deep-rifle' by the button method. I had one such barrel, a .36 that hurt the eyes when looking through it, end to end - when shoving a ball down, or cleaning, you could feel the loose and tight spots, which were only about 1/8" apart, all the way down the tube DDDDDDDDDDDDDT- sound of the 'feel' Still, it shot well and won me a few matches at rondy - way back when. It had a generous crown and needed it's steel rod. I used a .375" ball and a .022" denim patch, if memory serves. It didn't like the more normal sized .350" balls my wife's .36TC shot so well.
Bauska barrels, back then, were better shooters, normally. Deep-hole buttoning doesn't work well as the metal pushed out, comes back in slightly, making the wavy interior.
Perhaps not all his barrels were like the one I had.
I'd much rather have a GM barrel.