Like Cayugad, I hunted with a ML long before they became popular and before there were special seasons. And also like he said, all we had were RBs, Maxis and Minnis. If there were other hunters around they would either snicker at my ML or were intrigued about it. I shot my first ML deer about 1969 with a .45 PRB from my T/C Hawken fliner at about 35-40 yds. She ran about 50 yds and piled up. A few years later I 'graduated' to a .50 flinter when PA started their primitive season. And then only PRBs were allowed, and buckhorn style sights and flintlock ignition, 44 cal or larger. Today you can still only use open sights and flintlock but the projectile is anything you want to use. Bore size must be .44 or larger.
There is an early season in mid October where you can use any muzzleloader and any sights (including scopes) and any projectile. But the bore still must be .44 or larger. And this year you can use a ML pistol, .50 cal min.
I plan on using my .54 1:70 with PRB and carry my Lyman .54 Plains pistol in case I get a shot <25 yds.