Yep, they are cleaner - and weaker. Also, if you're using pelletized powder a regular 209 primer is so powerful that it will actually move the charge and bullet before the powder ignites. This reduces accuracy. No big deal if you're shooting at closer ranges but I'm working on a longer distance load for Antelope next fall. As Tx says they don't work with BH powder but they are great for Pyrodex and 777. Hopefully sooner or later I can turn up a few.