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H-A style underhammer

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NorthFork

40 Cal.
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I've always been intrigued by underhammers ever since I saw a H-A decades ago when I was boy. I would like to build one. Pecatonica River has a H-A style kit that I'm interested in. Has anyone built an underhammer from one of these kits? What is involved in building one? I know that the buttstock is drilled for the through bolt and basically inletted. How much wood removal is required to finish shaping the stock? I guess what I'm asking is, is the buttstock and fore-end in the white or just crudely inletted and roughly shaped and the rest is up to me? I know dovetails will need to be cut for the sights. I know the breechplug will need to be fitted. The location for the nipple will need to be spotted and drilled and tapped. How does the fore-end attach? How does the ramrod thimble attach? I also have heard that these H-A actions are not that durable. The half cock and full cock notches tend to chip out. Can anything be done to avoid this and can spare parts be purchased without having to purchase an entire new action? Thanks in advance for any information on this.
 
NorthFork said:
I've always been intrigued by underhammers ever since I saw a H-A decades ago when I was boy. I would like to build one. Pecatonica River has a H-A style kit that I'm interested in. Has anyone built an underhammer from one of these kits? What is involved in building one? I know that the buttstock is drilled for the through bolt and basically inletted. How much wood removal is required to finish shaping the stock? I guess what I'm asking is, is the buttstock and fore-end in the white or just crudely inletted and roughly shaped and the rest is up to me? I know dovetails will need to be cut for the sights. I know the breechplug will need to be fitted. The location for the nipple will need to be spotted and drilled and tapped. How does the fore-end attach? How does the ramrod thimble attach? I also have heard that these H-A actions are not that durable. The half cock and full cock notches tend to chip out. Can anything be done to avoid this and can spare parts be purchased without having to purchase an entire new action? Thanks in advance for any information on this.


A lot of questions in that post. I'll respond to a couple and let real experts chime in on the rest. If the breech plug is not already fitted, I suggest you have Pec do it. An improperly fitte breech plug is bad news in many ways, possibly dangerous. I was going to suggest you start the project by acquiring a very long screwdriver. Either at flea markets from maybe Harbor Freight. Say that because the original H&A underhammers I used to have and sell had a short screw holding the stock onto the breech assembly. That required a long screwdriver to reach it. But, the Pec illustration seems to show a long screw. If that's correct it would eliminate the need for a long screwdriver.
 
Just one thing that I don't care for in the latest batch of H&A style guns is that the fore end attaches with a screw. Original H&As attached with pins, like a full stock and barrel might be joined. The H&A I assembled in mid '70s used pins, two through the forend. I don't recall if it came with escutcheons or I added them. The pins pass through holes drilled through the barrel just above the edge of the bottom flat. To my way of thinking pins are a more period correct way of doing things.

Another thing I like about the old H&A rifles is that the barrel was attached to the frame using a tapered cross pin, a #1 Morse taper I believe. The copies seem to all have the barrels joined using three set screws, one from each side and one from the top. The cross pin is a more elegant solution and also more historically correct in my estimation. It certainly draws the barrel very tight to the frame, and the barrel on my gun has never ever come loose. The pin only moves when I tap it loose with a small hammer with a plastic head.

The mainspring/trigger guard of a modern kit may need to be tempered. The one on my Deer Creek kit was soft.
 
Hmmmmmm.....I was afraid of that. Seems like there are a handful of problems with the H-A type action with no easy solutions.

Edit- I'm referring to the soft mainspring.
 
My H&A has one barrel pin and two forearm pins. I like it, an elegant solution. Just...well, unlovely.

I still need the thread of the thimble screw...HELP!
 
The spring isn't hard to temper. A little study will get you started. No special stuff needed. Heat it with a propane tourch and draw the temper in your stove oven or by laying it on top of an electric stove burner. It's a thousand steps behind rocket sience.

If you want to pin the fore stock on, If the piece is square to start with, like the Deer Creek item, it would be easy to drill the holes for the pins by aligning the wood to the barrel and laying it on the drill press table and drilling through the wood and steel all at the same time.

I want to modify my Deer Creek to take a tapered pin to secure the barrel to the frame, making it like the old H&As.
 
Pinning vs the current screw method for the fore-end does not bother me as I was not really set on using a fore-end anyway. I've seen lots of pictures of both original and reproduction underhammers without any fore-end what so ever. As for the set screw vs pin method for securing the barrel to the frame, I was going to buy some slotted head set screws from McMaster-Carr or just make them myself. Slotted screw heads would look much better than hex heads. Maybe not quite up to the standards of the originals but less objectionable than the hex head set screws. However the complaints about the current production repro H-A actions have me concerned. You say you had a weak spring. I've also heard that the hammer and trigger can be improperly heat treated and that leads to trouble soon down the road. A lack of parts to fix these problems puzzles me as well. From what I can tell, I would have to buy an entire frame to replace say a broken hammer. It's my understanding that the same company that makes the H-A also makes the Allen box actions. The box actions seem to be well received. I wonder why the H-A actions seem to have troubles. Maybe a phone call to Pecatonica is in order.
 
The Target Model of the U/H ,,H/A did not have a fore arm .
Difficult for me to understand where/what problems a U/H could have,it is as basic and an anvil,Very few parts to break/wear out.
 
Just got off the phone with Pecatonica. Nice guy to talk to. He said that 3-4 years ago the various parts did have a heat treat problem. Mostly too hard. That has been cleared up now and no more problems have been reported in the last couple of years. He also said he sells a bunch on these so they must be somewhat popular somewhere.I'm likely going to call him back this afternoon and order a kit. Gotta decide on caliber.
 
used 1 of his kits recently, very nice, got the grade 4 curly maple, again, very nice!!!!
 
In the FWIW column, many years ago, I built one of these:
http://blackpowder.biz/

The Blue Grouse version of the H&A was well done, but it is still an H&A style. Mine was set up for a screwed on, fixed barrel. It uses a .45 Badger barrel with an 18" twist, for paper patched bullets. I have killed many deer with it, one at 200 yds, but I don't particularly care for the gun. The shape of the action and through bolt system puts a lot of constraints on the potential shape of the overall rifle.

Getting the nipple far enough in front of the breech plug and yet reachable by the hammer, is also a bit of a trick. That can lead to quickly fouling out, depending on how you manage your fouling between shots.
 
My cousin gave me this action when I was home visiting the farm in Michigan two winters ago.
I've made quite a few modifications on the H&A action on the rifle pictured. It originally had the taper pin but I didn't care for it and threaded the front of the action. Also extended the trigger shank to the rear of the bow spring and added the flat iron pistol grip and nipple flash divert-er.
 
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