Shotgun 209 primers tend to be less accurate and more mess (diffently more dirty powder residue)than use of ML 209. Quote"The shotgun primers are the hot ones andclaims topush the charge out of the barrel faster than it can burn all the powder charge up" There maybe some sort of truth to this in that the ML primers do seem to be more consistant in the accuracy catagory where the shogun primers seem to be a larger groups, with fliers. This pretty much holds true on all muzzleloaders we have shot in my area. Of course there are always exceptions to every rule and situation. And powder kind (loose or pellets) can make a huge difference as well. I personally think it has a lot to do with how tight the projectile is in the barrel as well. Some of these ML go from (the bullet/sabot almost falling into the barrel, to others you have to stand on the ram rod to get it down the barrel. My advice is experiment and use what works best for you. I've seen suppose to be the same gun shoot totally different than one just like it? Shoot, shoot, then shoot some more to be sure, what your "sweet spot" load is?