I shot a great deal of BPCR before the NRA got involved with sanctioning and rules. The NRA rules were established by the manufacturers to exclude whatever period guns they did not like and to allow whichever the manufacturers made. We were shooting original guns in competitions back in the early 1970's. Any gun or replica of a gun made, sold or issued in North America before 1880 was legal. Didn't matter what kind of action. or what kind of cartridge.
Then the NRA and it's minions brought shooter classes, etc. A newbie got thrown automatically in the top class just to scare him off. You couldn't use an H&R because of the ejector, another move designed to keep out the newbies.
The rules were contrived to sell expensive guns and even more expensive sights. Last time I competed under NRA rules, with a Trapdoor, I shot a 27 out of 40. But the powers that be changed the rules by the next time I showed up. No more wiping between shots was permitted. Just so much road apples.