Don't use Blue Dot for this application. It is meant for high brass shotgun loading, and is a dangerous powder for magnum pistol and rifles. Ed Matunas, often considered the foremost authority on reloading in the country, said Blue Dot bears the dubious distinction of being the only powder with whichhe has ever "blown up" a gun. A starting load with a 110 gr. bullet in a .357 Magnum blew the cylinder of a model 19 Smith and Wesson up like a hand grenade. Ed narrowly missed being injured.

I haven't destroyed a gun with Blue Dot, but have had it go into a sudden "detonation" mode where pressure unexplainably spike in the red zone.

For the .223; I use RL 12, H335, or BL-C(2).