Phil Sharpe's 1937 book "Complete Guide to Handloading, had a whole section on muzzleloading. First time I read it I learned that the precision shooters used a false muzzle to to start their bullets, and that the muzzleloaders had / have a national association, still active.
So, based on that cartridge guns were to the fore, but there was a powerful interest keeping the original smoke poles going......front runner of the BR crowd. Book is available for down load from:
https://www.milsurps.com/showthread.php?t=27114