ok tired of you guys wolloring this to death using the wrong fix. first let ,me give you some of my back ground.
in 1999 i received 2 savage 10 50 cal smokeless muzzleloaders. so i worked up loads for 17 years. light loads, accurate loads. you name it i shot it. now what's that to do with you guy's problem ??? the flash hole. most muzzleloaders with breech plugs the flash hole diameter is large .040"-.050". on smokeless ML's they are .032" to.034". so if you use a .032" breech plug you'll have no problems shooting black horn powder as the pressure will never get high enough to raise the striker. the catch yes there's a catch. you need to use a primer removal tool or buy a mz loader that has a bolt that also removes the primer. i use the separate remover on my custom ruger no. 1 45 cal .