so I'm playing Gunslinger in our current game, however, I really find the limited selection of weapons currently (muskets,  flintlock pistols and blunderbusses) limiting and boring. so I've been allowed by the DM to design whatever simple yet slightly more advanced weapons that I want too. Now this is why I'm here, if I want to use any weapon that is actually interesting and seems like fun I need to make a logical (rough) design for a bullet instead of a crap little ball. I've come up with pretty much the whole design, all that's left is that I need to find out what to use as a primer and that is why I'm here. my original concepts for a primer (in case it gets you imagination stirring) was to use alchemists fire but it burns when in contact with air which wouldn't work well for a bullet... Any and all suggestions are appreciated just keep in mind the DM must approve it before i can even start designing in-game

Look at designs for the Rifles and miniballs (not actually a ball, just the name) from the American Revolution period of history.