The MK-85 is a hammer striker model rifle. Even if it has the red primer 209 jackets I am not sure it would give you good results, but I am not 100% sure of this. With out a 209 ignition system forget even trying Black Horn. I have shot BlackHorn out of my Disc with the orange primer jacket and it worked fine. I also tried it in a Black Diamond XR with 209 but no jacket. It fired, it hang fired, and it blew primer all over the place.