flmason,
Blackhorn 209 is a Black Powder SUBSTITUTE. It creates pressures very similar to Triple Se7en loose powder.
http://www.blackhorn209.com/http://www.blackhorn209.com/files/pdf/brochure.pdfBasically any modern 209 rifle with an enclosed 209 primer pocket, that allows the breech/block/bolt to lock up tightly on the primer. This powder is not for #11 caps, Musket caps, any of the small rifle/pistol primer conversions, or the 209 plunger action type rifles.
Some production rifles that I know work would include.
Knight: Disc Extreme, Elite, KP1, Vision, Shadow.
T/C: Encore/Pro/Endeaver, Omega, Triumph.
CVA: Accura, Optima/Pro/Elite.
Traditions: Pursuit/LT/Pro/II.
H&R/NEF Huntsman/Sidekick with aftermarket Metrics Unlimited breech plug.
Savage: ML10II.
The Rossi and MDM tip-up rifles should probably both work as well?
The Knight KRB7 is not reliable, the breech block has just a little too much play, and therefore loses it's pressure seal at ignition. For Blackhorn to work properly, you need Pressure, Heat, and Time. If any one of those is missing, you will get hang-fires, or even misfires occasionally. This is also why you need the HOTTER 209 shotshell primers for sure-fire ignition, not the special 209 muzzleloading primers. If the primer is allowed to move rearward in the primer pocket, then you lose both heat and pressure. It is also better to have a .031" to .040" flash hole for ignition.
Extremely cold air, loose breech blocks/primers, and small flash holes are the enemy. Some would say loose bullets as well, but I know that is not the case in every instance. I have shot some bullets successfully that nearly slid down to the charge with just the weight of the range rod.