Old it may be, but as we say here, 'is féidir fonn breá a sheinm ar sheanfhidil' - 'many a fine tune is played on an old fiddle'.
Of course, some of the fun is taken out of it here in UK, where we have to go through the nausea of getting a Firearms Certificate in order to shoot it legally.
Apropos BP competition shooting in the USA - I know you like to think of yourselves as entirely separate from the rest of the world with regard to shooting, but the MLAIC [The Muzzle Loaders Associations International Committee] is the world governing body for competition with muzzle-loading firearms. It is truly international and even Americans have been known to participate at world-class levels of competition.
This here is a handy little book by the well-known British BP pistol shooter, Derek Fuller -
ISBN 1-86126-482-8
The author is well-known in UK BP circles for his many successes in both UK and on the international scenes with a variety of BP target pistols, mostly originals, although he is very much taken with the Hege Siber pistol*. He is retired, and has a long history as President of the Cheshunt Rifle and Pistol Club - itself over 120 years old. I fully appreciate that those of you in the USA have your own experts in the field, but I have yet to see any similarly-dedicated work produced in the USA. I firmly believe that expertise in any sport is something that transcends international boundaries. Unlike many other similar publications emanating from Europe, you won't even have to translate it!
* I was similarly impressed with the example with which I shot my first [and last] 95, so much so that I was very tempted to prise it out of the owner's hands by forcing money on him. Sad to say, although I could have managed the $750, the additional '1' in front of it was an instant game-killer.