What's the best 209 primer fired muzzy?
This is just my thought... I use the Winchester W209. If you are going to make the switch to 209's & BH-209 powder the correct primer will depend on the breech plug installed in your rifle.
Since BH requires a much higher ignition temp, you will see that Western Powders suggests a 'mag' type primer. But again it really depends on the BP in you rifle.
Both Western and CVA offer an aftermarket BH209 breech plug
If you have a Knight the existing 209 BP's and a W209 will work great!