I don't give a rat's a$$ about receiving an apology. Obviously, I didn't know about later models of the Huntsman-----but I certainly know about the gun I owned.
It was a .45 caliber, with a knock-out breechplug that could be removed when the gun was opened. H&R had simply taken their shotgun frame and put on a muzzleloading barrel. It opened as far as a cartridge-loading gun. There had been no user modifications.
The fouling seemed to come from blowback through the nipple, a recognized phenomenon in sidehammer guns. The gun fouled quickly and badly, with black powder or Pyrodex (the only propellants then available). The fouling caused the gun to pop open when fired. It froze the firing pin. If the pin was out, it caused the gun to fire when closed. If the pin was in, it wouldn't fire. When a percussion gun fails to fire, you replace the cap. That could have killed me, had I experienced a hangfire.
I stand by my assertion that this gun was one of the most dangerous firearms produced in the 20th century. If anyone knows of a more dangerous one, by all means let us know.
BTW, since the article about the breechplug injury likely appeared in something like the American Journal of Radiology during the pre-web era, you're unlikely to find it with a google search.