I am sure it could be done, as my Ultra Mag is a model 97 and it has a special hammer and nipple that allows me to shoot 209 primers. But the real question is, even with the converstion, this is still an open breech rifle and it might not shoot BlackHorn 209 well. I think Sabotloader tried BlackHorn 209 in his White Ultra Mag, so he would know for sure if they will handle it.

With the way the White Rifle is set up, I personally would stick with a standard #11 nipple and shoot black powder or a substitue that works and provides good accuracy. The advantage of the Black Horn powder is no swabbing, and easy clean up. You brother in law already has that shooting a White. I shoot 20 rounds without swabbing and I never found the simple open breech design of the White (or any other rifle for that matter) very hard to clean.

Perhaps Sabotloader will answer this thread and tell you whether the rifle likes the new powder or not. I have BlackHorn and three Whites, but have no intention of changing over to a 209 ignition to try the powder. They shoot too good the way they are..