Breech, you can use a percussion or inline only during the one week early ML season. You can also use these during the regular rifle season. However, in the late season, Dec. 26 to some time in Jan, you can only use a flintlock. As far as projectiles, anything you can stuff down the barrel is legal. ML caliber must be 44 cal or larger for long gun and 50 cal or larger for ML handgun.
And yes, crossbows were legalized this year. But frankly I have no desire to own one. I really have nothing against them. Its just that I can shoot my vertical bows really well. Maybe when I get old and feeble like Semisane..??