Not a lot of expierence here with BH209,but I have a CVA and switched to BH209 for my Colorado elk hunt. I shot the TC Maxi ball and ordered the new breech plug to use with BH209. I have not had any problems with ignition or accuracy out to 100 yards. My maxi balls load tight and I need a starter to load them.
I noticed a couple things on the last posts. One was the bullet was coming out of the barrel after a couple shots, but did not go far. That sounds like the primer and powder are igniting but no back pressure like has been said. Are you pouring powder out of the barrel after the shot? If not then it is burning, just no pressure. Not sure how much a barrel will expand or contract being loaded inside then being taken outside in the cold for a while, but if that's an issue then the bullet being used is close to being to small to begin with. It was also mentioned that if the bullet is hard to load then you must take your gloves off. They should be tight to load each time, even the first time. Another issue is the powder not burning correctly when it has poor ignition will leave a lot of debris or fouling in the barrel making it unreasonably hard to load. It would need to be cleaned each shot if the powder is not burning correctly. BH209 can be shot a lot without cleaning on proper ignitions.
I am going with the loose bullet theory most have mentioned. Load a tight bullet and make certin the ignition system is clear and not fouled from prior poor powder burns.
Good Luck
