Hopkins and Allen .45 underhammer

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Semisane

54 Cal.
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Does the barrel have to be made by the Original Manufacturer to fit or can any barrel company make one to fit ?

I've made several barrels of various calibers for my H&A's. Two were from Green Mountain (link below), which are nice because they are already threaded for a 5/8" x 18 breech plug. At one time you could buy plugs from H&A. but those days are over. However, it's not difficult to fabricate a plug from a 5/8" x 18 steel bolt. One was a barrel blank of unknown manufacturer I bought at a gun show. I had to thread that one for the plug. If you're a bit handy with tools it's a fairly simple job to set up a new barrel for these sweet underhammers.

BLACK POWDER MUZZLE LOADER BARRELS - Green Mountain Rifle Barrel Co. (gmriflebarrel.com)
 
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I've made several barrels of various calibers for my H&A's. Two were from Green Mountain (link below), which are nice because they are already threaded for a 5/8" x 18 breech plug. At one time you could buy plugs from H&A. but those days are over. However, it's not difficult to fabricate a plug from a 5/8" x 18 steel bolt. One was a barrel blank of unknown manufacturer I bought at a gun show. I had to thread that one for the plug. If you're a bit handy with tools it's a fairly simple job to set up a new barrel for these sweet underhammers.

BLACK POWDER MUZZLE LOADER BARRELS - Green Mountain Rifle Barrel Co. (gmriflebarrel.com)
So If I were to buy a .58 caliber barrel from green mountain and as long as it had a 5/8x18 Breechplug I could just attach it to the rifle and add some sights to it ? Or is there more work needed ?
 
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i may be wrong but i think these do not have a half cock notch [?] if so not the best for hunting.
I also hunt with a Martini unmentionable during open firearms season and that rifle has no safety at all. Usually only use half cock when I put powder in the frizzen and if I am sitting in one spot I don't fill the frizzen until a target presents itself, other than that it stays fully depressed.
 
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The H&A has a half cock notch for a safety.

You can install almost any brand barrel on one of these provided you have it breeched properly. You will also have to locate and drill and tap for a nipple.

I'm of the opinion that the 20" barrel gives up too much to be a good deer rifle but It's a a super handy lightweight gun for plinking.
 
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The H&A has a half cock notch for a safety.

You can install almost any brand barrel on one of these provided you have it breeched properly. You will also have to locate and drill and tap for a nipple.

I'm of the opinion that the 20" barrel gives up too much to be a good deer rifle but It's a a super handy lightweight gun for plinking.
What is a minimum barrel length to be a good deer rifle ? I only ask this because my Bess has a 42" barrel and I don't own anything relatively smaller. On a second note it I were to purchase a .58 cal barrel with same breech plug all I would have to do is have a hole drilled at the bottom for the nipple to screw into ? Lastly excuse my ignorance but do all barrels have the usual tang found on traditional rifles and a side hole already drilled out ?
 
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I wouldn't go with under a 32" barrel and would prefer a little longer.

You can buy barrels without the tang (breech plug) and not machined for a breech plug. As far as getting a new barrel with a H&A plug good luck. It's a DIY situation or have someone do it for you.
 
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I wouldn't go with under a 32" barrel and would prefer a little longer.

You can buy barrels without the tang (breech plug) and not machined for a breech plug. As far as getting a new barrel with a H&A plug good luck. It's a DIY situation or have someone do it for you.
As of right now my boss found a 31" .45 cal barrel that is setup for the under hammer in another box of his inherited rifles and parts which he thinks goes to this rifle he will include it with my purchase. My buddy has a traditions kentucky with a 33" barrel and takes many deer does a loss of 2 inches of rifling stifle power that much. I only use smoothbore so hunting and bowling have a lot in common in that department.
 
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I had one in the 70’s. It did have a longer barrel on it. The sight was an open rear
Aight but I had a globe front sight with a small post inside the globe. It shot one ragged hole groups.
thenunderhmer is extremely fast ignition as the nipple fires right into the chamber.
I shot it in local matches at the time.
you won’t go wrong for $250. That is a deal.
I would jump on it if it were me.
 
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Had a buggy rifle for years, had to let ti go when I got laid off several years ago. Been trying to buy another ever since, even got scammed here on the forum trying to buy one. Buy it, it's a fun gun all round!!
 
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What is your load for the rifle ? Is it like a .440 ball and .015" patch ? How many grains of powder do you find well ?

I can't help you with the powder charge, but I think those bbl.s were set up for a .443" RB. Btw, they were once quite common around here as Numrich Arms was/is not far from my home and was well known as a parts/gun shop years ago.
 
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I was primary a hunter, started with a 50 FL for a few years in 1970. Next step was a H&A Under Hammer in .45, and yes I got my Deer each year, bullet placement the most important with a 45 RB. My next was a H&A Under Hammer in .58. But I had H&H build me a barrel for Minies with progressive depth rifling for accuracy. I built both from kits and installed tang peep sights. The range targets I always kept so I could remember my loading for next season. Notice on the top target my RB size and I only worked up my load off hand as that was how I hunted. What I do have is the un-fired .58 barrel still kicking around going on 50 years.
 

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The only H&A I examined was one with a shattered barrel from the early 1980's. I think the poor guy had trouble loading it so fired with a large gap between powder and ball. It was a Douglass barrel. Accurate, but they may shatter now & again. I do have an H&A pistol from maybe the late '60's.
If you get this rifle do re-barrel it if that barrel is marked something like GR Douglas.

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December 1972
 
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In was in search of flintlock rifle when my Boss came up to me with an offer to sell me his Hopkins and Allen .45 Caliber underhammer rifle. It is a .45cal rifle with a percussion ignition and a 20" barrel. Anyone know anything about these and if it's worth buying. I would be using it for Whitetail Deer hunting if I do purchase it. It would cost me $250 to buy it from him but I know nothing about it and I don't even know if it is a good hunting rifle or not. Any information or insight is much appreciated.
Was probably sold by Numerich in the 60s or 70s. Undoubtedly has a round ball twist barrel. My roomie had one, it was called a ’buggy rifle’. It was
very accurate. Would be ok for short range deer work (50 yds and under).
 

Semisane

54 Cal.
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So If I were to buy a .58 caliber barrel from green mountain and as long as it had a 5/8x18 Breechplug I could just attach it to the rifle and add some sights to it ? Or is there more work needed ?

Not quite. None of the GM barrels with breechplugs will attach to the H&A action. What you want is the .54 or .58 barrel without a breechplug, but with 5/8 x 18 threads for a breechplug. Then use a 5/8 x 18 bolt from a hardware store to fabricate a breech plug for the H&A. You will also need to drill and tap for the nipple after the breechplug is installed and the barrel fitted to the action. You want to have the barrel installed so as to locate the proper spot for the nipple.

As an alternative, have that extra 31" barrel re-bored to a larger caliber by Bobby Hoyte.
 
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