Recently picked up a nice little older custom build and the barrel has me stumped. I would put the build late 80s at most but the barrel is really interesting. There are no builder marks at all but the bottom flat is actually marked "TOP" with a Sharpie so either it breached better 180 degrees out and any maker marks were draw filed and browned away, or possibly the entire barrel was machined to a smaller profile. It's a 13/16" .40 with 1:48'ish twist and 6-land/groove rifling.....but it's ROUND BOTTOM. Much shallower grooves than my Rice and Colerain round bottom barrels too. Is anyone aware of a barrel maker from the 80s that was playing with round bottom rifling???