:lol: Well, I can answer that, because I have a new Huntsman 50cal rifle bbl for my 12 Tracker II, and just last week bought a Huntsman 12ga shotgun that was made in 1974
The older model (156) Huntsman has a breech plug that slides in to a "chamber" in the bbl like a shotgun shell. It has a delrin and a rubber "O" ring sealing off the breech plug. A conventional 1/4-28 nipple for #10 or #11 (#10 work best on mine) percussion caps.
When you want to thoroughly clean the bbl, you remove it from the action, and use a ramrod to press the breech plug out, and you then clean the bbl like any other rifle or shotgun, using the proper cleaning solution, and clean the breech plug and nipple separately. BTW, mine has a large, flat firing pin specifically for the percussion cap, and CANNOT be converted to centerfire ammunition.
The newer Huntsman barrel has the following differences:
1. The breech plug is threaded, and must be removed with a special tool provided with the bbl.
2. There are no "O" rings used or needed to seal the breech plug.
3. A percussion cap nipple is not used, nor are conventional percussion caps.
4. Ignition is performed using "#209" shotgun primers, held in place by a special holder called a #209 carrier". This carrier is unique to H&R/NEF, and NEF says that they are good for about 5 uses. I think that people are actually getting more uses from each one.
5. The new NEF Huntsman can have a (centerfire) shotgun bbl added by the factory, and a current model NEF/H&R centerfire rifle or shotgun receiver can have a new Huntsman bbl fitted by the factory. Because of this, a new or current gun that is originally purchased as a Huntsman has to be purchased as a regular firearm, with all the checkout and paperwork involved, since BATF does not consider it a "NON_GUN"
6. I think the new type is not as easy to clean, mostly because of the breech plug threads, which have grease on them to keep the plug from seizing up in place.
OLD TYPE HUNTSMAN BREECH PLUG
NEW TYPE NEF HUNTMANS BREECH PLUG
