No idea. I was hoping someone else would take up the “quest” but searching “underhammer” is pretty fruitless.
When I first saw them years ago, I think they were $1500 or more, outta my reach then for certain. The last ones wereway up there, maybe $3k? There was a .72 African with dual cap ignition IIRC for the heavy charges.
Another outfit, October Country I think made .62 slow twist guns too, but sidelocks. No idea about their current stuff. At my age, 200gr or so of powder is probably best left to conjecture, not experienced😱
