H&R Huntsman Breech Plug and Nipples Leaking Spark?

[Slick Pilot]

I have a second hand H&R Huntsman muzzle loader in 58 caliber that I believe was manufactured in the 1970s. It has a press-in breech plug with a slot in the top rear that mates up with an identical slot in the top of the rear of the barrel. I cannot find a picture of a breech plug and barrel for the Huntsman with the slots in the top of both as described. No parts manuals are easily found.

Upon testing the ignition with number 11 cap, sparks come up through the slot(s). I changed to a 209 primer nipple, laid a folded paper towel across the top of the slot, and the force of the spark from this blew a hole upwards through the two layers of paper towel.

I have fired percussion cap rifles before and have never noticed sparks escaping from around the caps. The nipples and the breech plugs were clean and clear of obstruction.

Anyone have any advice? Thanks!

I POSTED PHOTOS IN #7 BELOW.

[megasupermagnum]

I'm not familiar with that at all. Can you post a picture? All the push-in ones I've seen were round, sealed with an O-ring in the chamber. They were flush with the back of the barrel so in theory all the stuff was contained inside the plug. All of the threaded plug ones I've seen had a slot cut in the barrel, but it was to accommodate the orange carrier for the primers.

[Slick Pilot]

megasupermagnum, I will try to post photos tomorrow.

I POSTED PHOTOS IN #7 BELOW.

[Gtek]

Not familiar with the H&R but the early CVA Spanish and also my TC Black Diamond breech plugs vent the 209. The early Apollo has a slide cover and vent hole in bottom of stock, and you can see the venting designed into plug face. The TC plug with interchangeable 11/209 inserts smoked the bottom of my Leupold scope. How's things these days out at old Mother Rucker?

[RustyReel]

Sounds like that is the model that used the plastic cap holders. Not sure what they were called.

https://www.gunbroker.com/item/920607647

[Shawlerbrook]

296519

[Slick Pilot]

296546296547296548296549296550

Photos attached. If I did it right.

[rockrat]

I have two of the 58 cal barrels and neither has that slot. Why not rotate the breechplug 90 degrees so you won't have sparks coming out of the gun when you fire it.

[RustyReel]

Don't think that is from the factory and have no idea why someone would do that.

[Shawlerbrook]

I think we have a bubba custom muzzleloader. Over on Graybeard they have some experts on H&R/NEF guns.

[Slick Pilot]

rockrat

That might work. Will advise.

[Shanghai Jack]

Breech Plug and Nipples Leaking Spark - I hate it when that happens!


I think we have a bubba custom muzzleloader. Over on Graybeard they have some experts on H&R/NEF guns.

Agree - wouldnt think the factory would let it go with the obviously munged up cut on the left side of the slot.

[John Taylor]

Many years back Idaho passed a law about the muzzle loading hunting season saying the rifle had to use a precision cap and it had to be exposed to the elements. I had made about 2 dozen muzzle loaders from old shotguns and they were doing great using 209 primers but with the new law some of the rifles were sent back to be altered. The rifle pictured is not one of the ones I did but has a similar cut. I don't know if any other states past this type of law. All the ones I did had a threaded breach plug. Most percussion caps will throw sparks. sometimes the hammer will shield the sparks so they are not noticed. On this type of setup there is no shoaled and the spark will be seen. As was suggested, turn the breach plug over.

[Maven]

And give it a couple of wraps of teflon tape before you reinstall it.

[Shawlerbrook]

Mystery solved.

[megasupermagnum]

I've seen worse. I'm guessing someone drilled a hole, then cut the extra off with a grinder to get the slot. It appears to be a safe modification, other than the blast from firing. This is why I'll never support restricting muzzleloader seasons. Now there's a butchered H&R just because some guy with a CVA percussion gun thought he was better, and "fixed" the problem with government.

[Slick Pilot]

rockrat

I did rotate the plug 90 degrees as you suggested. Then I placed a folded paper towel over the top and popped a #11 cap. A smaller hole was blown through the towel this time but the black discoloration was distributed around the circumference of the breech. Gas is leaking around the mating of the cap and the nipple. Also the cap is pretty near destroyed and flattened out.

Is it possible that the gap between the nipple and the firing pin is to great and allows the cap to be pushed back and flattened, thus allowing gas to escape into the back of the breech and to the outside?

Many thanks.

[megasupermagnum]

No, that is normal for these to blow up caps like that. If you hold it up to a light, you should not see any light between the breech face, and the barrel face. If you do, you can add a shim to the hook of barrel to tighten it up. Or you can live with it as is.

[longbow]

I had a .58 Huntsman back in the 70's. It had the push in breech plug as well.

I made a similar but much smaller notch through the right side of the barrel breech face and breech plug
by using a chainsaw file to make a half circle notch. I found that there was enough blow back through the nipple to crud up the breech face so the action wouldn't close after a few shots. I filed the notch to allow venting of smoke and crud... that worked for me.

I guess I could have regularly wiped the breech face but figured that venting would solve the problem. It did.

That is a pretty big notch in yours but it it works I wouldn't worry about it.

Longbow

[John Taylor]

rockrat

I did rotate the plug 90 degrees as you suggested. Then I placed a folded paper towel over the top and popped a #11 cap. A smaller hole was blown through the towel this time but the black discoloration was distributed around the circumference of the breech. Gas is leaking around the mating of the cap and the nipple. Also the cap is pretty near destroyed and flattened out.

Is it possible that the gap between the nipple and the firing pin is to great and allows the cap to be pushed back and flattened, thus allowing gas to escape into the back of the breech and to the outside?

Many thanks.

That would be normal for percussion caps. I have seen a few H&Rs that have had half the rear cut away.

[dk17hmr]

My 58 cal has an identical cut through the barrel and plug. Mine also has a indexing pin up through the barrel lug that indexes the plug. I assume it was done to meet the exposed ignition requirements of certain states.

Mine will gum up the firing pin in about 10 shots even with the 209 primer conversion nipple.

[rbuck351]

I have one of the first Huntsman guns with the thread in breach plug. I lived in Washington State at the time and a year or two after the Huntsman came out they rewrote their rules saying the ignition had to be exposed to the elements so I ground out a 1/4" half circle similar to your gun but quite a bit smaller. Real easy to keep covered with a bit of quickly removed tape.