Hopkins & Allen question

[hanshi]

How about doing a new heat treatment on it. Anneal to soft, harden and anneal to correct tension.

No exaggerating here but the most mundane "fixes" are beyond me. Try opening a package of chewing gum while wearing boxing gloves; that would be my best try.

 

[hanshi]

Yeah, seems strange that no one makes a replacement spring for these things. I would pick up a few just to have some extras.

There has to be thousands of those guns out there; one would think replacement parts would be available. Sheesh!

 

[hawkeye2]

You're right, it doesn't have a flash cup.

That flash cup is still available.

https://www.gunpartscorp.com/products/1857470B
Numrich/Gun Parts Corp. still has some parts left but most parts sold out years ago.

https://www.gunpartscorp.com/gun-manufacturer/hopkins-allen/muzzleloading-rifles

 

[arcticap]

Thanks Hawkeye2!

 

[griffiga]

I'm assuming that what I have is a Hopkin Allen under-hammer. The only markings on the pistol are shown in the photo.

 

[hawkeye2]

It was built with H&A (Numrich) parts. Since it isn't marked and the serial number was done with an electric engraving tool I would guess it was built by someone other than Numrich. They sold parts and possibly entire guns as kits unfinished back in the 1970s and very possibly before and after that time. I have never seen a pistol marked other than by H&A but have seen a number of rifles that way. Some bore only the maker's stamp and others had both the maker's stamp and H&A and/or Numrich. It seems there was a fairly active market assembling and selling these. I wouldn't be concerned that it wasn't assembled by H&A, it is every bit as good as one that was.

That's a great photo showing the relationship of the trigger and hammer and the very prominent half cock notch, like a bear trap.

 

[griffiga]

It was built with H&A (Numrich) parts. Since it isn't marked and the serial number was done with an electric engraving tool I would guess it was built by someone other than Numrich. They sold parts and possibly entire guns as kits unfinished back in the 1970s and very possibly before and after that time. I have never seen a pistol marked other than by H&A but have seen a number of rifles that way. Some bore only the maker's stamp and others had both the maker's stamp and H&A and/or Numrich. It seems there was a fairly active market assembling and selling these. I wouldn't be concerned that it wasn't assembled by H&A, it is every bit as good as one that was.

That's a great photo showing the relationship of the trigger and hammer and the very prominent half cock notch, like a bear trap.

Thanks for the information. I acquired the pistol as part of a trade, but I haven't had a chance to shoot it yet. I need to pick up a new nipple.

 

[longcruise]

Can anyone explain how the interchangeable barrels are attached?

 

[hawkeye2]

The original H&A barrels were held to the frame by a round tapered pin which passed completely through the frame and through a hole in the breech plug. It was a tight attachment that worked well. Current ones are held by 3 allen screws, one from the top and one from each side. In all cases the breech plug is cylindrical and could be made from a bolt. The opening in the frame, of course, is round. You may see some folks using different methods of attaching the barrel, whatever they think makes for a better mousetrap.

 

[Ontario47]

Apparent weak hammer spring/trigger guard problem can be caused by wear of the rear mounting surface and/or screw or loose screw. Be sure the spring is held as far forward as possible and is not rocking on worn surfaces. A shouldered screw or shim in the front of the spring hole could help. A washer filed to a wedge thickness profile between the spring and mount pitching the spring up and forward could help. A shim between the spring nose and hammer spring notch could also help.

 

[hanshi]

Numrich Arms used the term "Boot Pistol" back when they sold underhammer guns. I don't think I'd want to carry one in MY boot.

 

[JIMHAY97]

Thanks for the measurements, that confirms the problem I was trying to tell others about earlier. I broke the trigger nose on my wife's H&A while working up a load and I have another that someone had done the same thing to. I had bought my wife's gun as a kit from Blue Grouse (no longer in business) and at the time Deer Creek was selling H&A kits and parts. I called them to get a trigger and explained to the nice lady on the phone why I needed one. She responded that I would need a hammer as well as it usually damaged the hammer (she was quite knowledgeable of the issue, seems to happen frequently). I tried to tell her I didn't need the hammer but she insisted and told me it was warranty, no charge. I told her I had bought the gun from someone else but she said they stood behind them, great people. I don't know if they still have any parts and they haven't listed parts or the kits for years. Hammers, triggers, breech plugs and sometimes a mainspring show up on that evil auction site from time to time.

Blue Grouse used to have a sketch of how to cut the half cock notch back but his site is long gone. It can be cut back quite a bit and not affect its function. If you do it in your jig could you post how much you cut off for everyone? It probably wouldn't hurt to file a slight bevel on the back side of the sear nose too. As is it's a right angle edge.

 

[hawkeye2]

In my previous post, #39, I made the following statement: "It probably wouldn't hurt to file a slight bevel on the back side of the sear nose too. As is it's a right angle edge.". Please ignore it, I really was thinking of something else at the time or at least that's my story and I'm sticking to it.

 

[JIMHAY97]

Thanks for the measurements, that confirms the problem I was trying to tell others about earlier. I broke the trigger nose on my wife's H&A while working up a load and I have another that someone had done the same thing to. I had bought my wife's gun as a kit from Blue Grouse (no longer in business) and at the time Deer Creek was selling H&A kits and parts. I called them to get a trigger and explained to the nice lady on the phone why I needed one. She responded that I would need a hammer as well as it usually damaged the hammer (she was quite knowledgeable of the issue, seems to happen frequently). I tried to tell her I didn't need the hammer but she insisted and told me it was warranty, no charge. I told her I had bought the gun from someone else but she said they stood behind them, great people. I don't know if they still have any parts and they haven't listed parts or the kits for years. Hammers, triggers, breech plugs and sometimes a mainspring show up on that evil auction site from time to time.

Blue Grouse used to have a sketch of how to cut the half cock notch back but his site is long gone. It can be cut back quite a bit and not affect its function. If you do it in your jig could you post how much you cut off for everyone? It probably wouldn't hurt to file a slight bevel on the back side of the sear nose too. As is it's a right angle edge.

Here is the small jig I used to measure the 2 notch surfaces. When I started the half cock was about .028 further out then the full cock. So after filing and polishing .030 off it now clears by about .002. The half cock has to be closer to the pivot point or it will hit. Point A has to be out more then B. In Sept 8, 2010 Roger Renner wrote a very good article in the Underhammer Society explaining all this plus discussed notch and sear angles. Hope this makes sense.

 

[hawkeye2]

Thanks JIMHAY97, great photos and an excellent explanation. I used to go to the Underhammer Society site years ago but must have missed the article. It's only one page now and very dated, is the article still up somewhere and does anyone have a link if it is?

 

[JIMHAY97]

Here is the small jig I used to measure the 2 notch surfaces. When I started the half cock was about .028 further out then the full cock. So after filing and polishing .030 off it now clears by about .002. The half cock has to be closer to the pivot point or it will hit. Point A has to be out more then B. In Sept 8, 2010 Roger Renner wrote a very good article in the Underhammer Society explaining all this plus discussed notch and sear angles. Hope this makes sense.

http://underhammers.blogspot.com/2010/09/underhammertrigger-geometry.html

 

[hawkeye2]

JIMHAY97, again thanks. That brief article and illustration makes everything very clear.

 

[JIMHAY97]

Just out of curiosity has anyone ever heated and bent the H&A hammer? I building a scratch built rifle with the only premade parts being barrel, trigger and hammer. I'm not happy with the way my hammer lines up with the nipple and would like to bend it to fit. I do know that the hammer is quite hard and don't want to soften the notches. I did the trigger guard/mainspring today. Think I may have overbuilt it. It works but takes quite the pull to cock it. I'll be thinning it down to tune it!

 

[Grenadier1758]

I haven't bent a H&A hammer, but I have bent the hammer for my CVA Mountain rifle and my Cherry Corners lock for my Hawken. It is a better practice to bend the hammer than to change the tumbler.

 

[M. De Land]

Just out of curiosity has anyone ever heated and bent the H&A hammer? I building a scratch built rifle with the only premade parts being barrel, trigger and hammer. I'm not happy with the way my hammer lines up with the nipple and would like to bend it to fit. I do know that the hammer is quite hard and don't want to soften the notches. I did the trigger guard/mainspring today. Think I may have overbuilt it. It works but takes quite the pull to cock it. I'll be thinning it down to tune it!

You can cut a piece out of the hammer shank and shorten it to fit the nipple center then weld it up and re-heat treat it. I removed the spur on my H&A to speed up the hammer fall . I cock it with a deer antler tine. I also cut the trigger shank in half , welded in and extension to move it back closer to the pistol grip I made for it.