I'm not sure your model is listed in this link below. But there are a couple posters here that modify breechplugs for shooting Blackhorn. So check back here the next couple of days.
http://muzzle-loaders.com/accessorie...reech-plug.php
Have fun with your rifle. In reading about it, the front sight is fragile and blowback will affect your scope. So you may want see-thru rings or detachable on it.
The good news is it's got a Bergara barrel, good trigger and recoil pad. Plus it has a thumb safety and solid stock. Not bad for an inexpensive rifle.