For any Mec equipment go to
www.mecreloaders.com or call them at 1-800-797-4632. Black powder creates some heat and may distort the end of plastic shells. You may want from Precision one of their " hull savers " [ pg. 19 ] to open up the shell. Wads are cheaper through
www.circlefly.com - tell Craig I sent you. You'll need around 7/16 above the shot for a crimp - it's not real critical - not like a star crimp. You'll find the 10ga roll crimper will work with 12ga as well. If loading smokeless the plastic wads are easier to use because of how much area that has to be taken up. A nitro load is small - 20 to 30grs where as BP is 80 to 110grs. That difference means more wads and too much can sometimes give poor patterns because the wads will tumble through the shot string. If you're gonna us more than 3/4" of cushion wads you should pattern your gun to make sure there's not a hole in the middle of your pattern. That's just my experience with brass shells. Also had problems with the thick over shot cards - went back to the .028 card. The Rem SP-10 wad works for less shot by useing a filler of some sort in the bottom of the shot cup. A navy bean, cherrio, 16ga 1/4" wad - anything to take up space. If star crimping you'll need more shot to end of shell - about 5/8" for a crimp.