On February 1st this year - I got an email from "Gordy Edwards" at Knight Rifles - and he assured me that the breech plug - part # 900046 - for bare primers, is made specifically to solve any problems with shooting BH 209. He said, he has been shooting it for over 2 yrs. with great results.
I have a Knight Vision rifle and also the new bp - but due to the deep snow, our shooting range is closed and I have to wait till warmer weather to try it out. I like the extra weight and the way the Vision comes up so natural - it feels real good and I think I'm gonna like shooting it better than My TC Bone collector.
Ditto, on keeping that flash channel clean. I use a 1/8" drill bit - just in my fingers - every 20 shots or so at the range. It's a must.
Not sure about the part# you mentioned. But i will tell you that that the plug was made before BH209 was on the market. And Gordy was the one that sent me the plug to try.
That plug is 100% not BH209 compatible.