I finally shot a few rounds thru my .50 cal Knight LRH and Elite rifles, using the FPJ plug with 100 gr BH209 and Winchester 209A primers and 290 barnes with yellow sabots. Got good ignition. Easy to load 2nd and 3rd rounds. I was able to easily clean the barrel with Hoppe #9 solvent. Breechplug was easy to remove with some carbon in the flashhole and nipple areas. Hand removed with drill bit. Have not shot for accuracy yet. I noticed a ring of carbon in the receiver area just in front of the nipple side of the breech plug. I have scrubbed the daylights out with brass brush and Hoppes. I can't seem to get rid of it. In my LRH, the area also appears to have a slight coloration to it, like intense heat discoloration. Never saw this with 777. I know the BH209 is supposed to have somewhat similar pressure curve as 777 , maybe lower. Does anyone know if BH209 burns hotter? Has anyone seen the carbon ring like I have seen? I like to keep my guns spotless, so I'm concerned about this and may dicontinue using it, though I like most other properties of it. If anyone can shed some light on this, i would be very grateful. Also, any suggestions on another product to get the mess out. I even soaked a piece of 00 fine steel wool ,and scrubbed hard. Still didn't fully clean. Thanks a lot. Really hate to go back to 777, but don't won't this carbon buildup.