So True Colonel. My father had 88 flintlocks in his collection when he died, and he did occasionally shoot a one. I still have a half dozen of the best ones. But I'd never shoot them -- after 200 years they are all questionable, even with a small charge. And, if you've ever shot a flintlock, you know how inaccurate most of them are -- even if rifled. I'll leave my 18th and 19th century weapons on the wall -- great history, but not for today's use. There are plenty of black powder repros that are made for modern shooting. My father used a repro Brown Bess regularly in ceremonies, but it couldn't even hit a modern target at 100 yds!
All my shootable antique collection is 20th century (WWI or II), military grade, well made from the start, and in good to excellent condition to start. I have no fears about loading a standard cartridge and pulling the trigger on these.