You want a Lehigh bare primer conversion kit. Its FAR better than the red FPJs for BH209. Plus the breech plug is made from 17-4 SS instead of 416SS. Its a MUCH better stainless and its cheaper than the Knight plug too.

Adapter that stays in the bolt. $14.50
https://sskfirearms.lehighdefense.co...product_id=258

Breech Plug with 1 vent liner $16.50
https://sskfirearms.lehighdefense.co...product_id=259

Extra vent liners $22. They last quite a long time but its a good idea to have extra.
https://sskfirearms.lehighdefense.co...product_id=282

Last plug i got was about $8 shipping and he shipped fast.