It done that with all new plugs i have used , it doesn't do that until around the 10-12 primers are shot off and then the carbon builds up so bad it starts blocking the flash hole and there is too much pressure from the primer and the only place for it to go is back and around the primer. You should see what it looks like when i try that in the dark , looks like the 4th of July next to my receiver !!! Then it gets so bad i stop shooting !! The only thing that helped was drilling out the small hole down the center of the breech plug , but (almost)everyone warned me against doing so saying it would increase the blow back from the powder going off and could be dangerous . So i went with the .25acp and 777 and its no longer a issue . I don't find swabbing once between shots with 777 any big deal and feel that BH209 is way over rated for the $$$ . I can find 777 everywhere and its cheaper and with the .25 acp conversion i bet my breech plug last forever using a weaker primer the seal i is 100% , no flash cutting .plus there is nothing around the firing pin to clean up and i will have less problem with that area . So i don't mind NOT using BH209 all all !!