Most of it has been covered but i wanted to emphasize using a normal powder solvent such as Hoppes #9 or Shooters Choice with BH209. I prefer Hoppes #9 Benchrest fomula in the gold bottle since i use it on other guns. MilSpec CLPs are good too...Clean Lube Protect in gallon jugs is cheap....$25 or less at gun shows.

Avoid Teflon based products in the bore or clean it out well before shooting.

Snug fitting sabots and/or heavier bullets work a bit better with BH209 in some guns. Its a bit harder to ignite and sometimes this helps more than a mag primer.

Use the proper sized drill bit with your fingers to clean out the flash channel (under the primer) in your breach plug. Sometimes it gets hard and a bit is one of the easier ways to remove it.

Whatever normal or mag primer fits your breach plug the best. I prefer normal primers in mine because they are usually cleaner.