They are not out of business Knight Rifles Hope this helps ya.
I Have a Black Knight( One of the first guns they made) I need a breech plug for it and have called nearly every gun parts place in the country(Knight I think went busted) Even checked with Brownell's in Iowa and hit a dead-end. If anyone knows where I can find one please let me know Thanks Tenncrappie
Try looking on Auctionarms.com or guntrader.com. They have gun parts on there, maybe you can find a dealer that has them.
Knight Rifles was purchased from PRADCO by a company out of Athens Tennessee. They are alive and well. You should have no problem getting a breech plug for your gun from them.