H A underhammer

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crgfrs

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Hi folks,
Just acquired a Hopkins & Allen .45 underhammer, I believe it's the heritage model with a with a peep screwed into the receiver.
Not a lot of specific information on this piece that I can find. I did find some threads here.
I've had a little experience with bp, had one years ago, tc hawken flint. I always found it difficult to shoot, although I did kill a deer here in Pennsylvania.
Anyway,
Boomer posted a load for his .45 underhammer; 1-18 twist barrel, slugs 455 gr, 90gr 2 f, .10.
I guess 455 is the ball diameter and .10 is the patch thickness.
Boomer if you're out there, I'd love to tap your experience.
Anyone else out there with one of these animals?
Bought it at a gunshow last week, was a deal I couldn't refuse.
Thanks,
Craig
 
I have one of the H&A underhammer pistols that I inherited. Clever mechanism. They made pistols and rifles in a couple of calibers with the same basic mechanism and with different variations, lengths, sights, etc.

For a .45 the ball size would be smaller, not larger (it's larger for cap and ball, which this isn't). Those H&As often had kind of undersized bores so you might want to measure it directly if you have a way to do that. Otherwise get some balls in the .43-.44 range and see what works. It's also a good idea to get a couple of different patch thicknesses and see what your gun likes.

For the load - this is the rifle? The standard advice would be to play with 45-90 grains and see in there where it is the most accurate. For pistol more like 20-45.
 
Hi:
I have 2 Underhammer rifles & two pistols.
+1 to EljaySL's advice.
Gotta play around with yours to find what it likes.
Eljay gave good starting advice.
--Dawg
 
Thanks,
It is a rifle, if I get a charge out of shooting it I may have to start looking for a pistol! I is pretty cool. I had seen photos of them before but never saw one in person before this.
I don't have a caliper to measure the bore so I'll try some of the different sized balls. Have you tried any of the sabot type/conical bullets in the guns? Start with 90 gr of 2F with a patched round ball?
Also, it looks as though the breech plug is removable from the barrel, anybody know if it is, just thinking of cleaning purposes.
 
You wouldn't get any kind of advantage with a conical or a sabot. Just go with the patched round balls.

I'd start on the low end of the range - 45 - and once you have a rhythm shooting it I'd work up by 5 grains at a time and see where the best accuracy is. It's more likely to be lower than higher. I'd use 3F but you can try 2F as well.

Messing with breech plugs is more of a last resort thing. I wouldn't do it for cleaning.
 
I have a H&A underhammer with the same fast twist barrel. It will not shoot large powder charges accurately with patched ball. Mine will shoot one hole groups with 30 grain 3f loads.
 
crgfrs said:
...
Boomer posted a load for his .45 underhammer; 1-18 twist barrel, slugs 455 gr, 90gr 2 f, .10.
I guess 455 is the ball diameter and .10 is the patch thickness.
Boomer if you're out there, I'd love to tap your experience.
Anyone else out there with one of these animals?
Bought it at a gunshow last week, was a deal I couldn't refuse.
Thanks,
Craig
Click to expand...
I am not Boomer but I interpet the load this way. Your rifle has one turn in 18" of length, in 45 caliber, this is a conical twist. The "...slugs 455gr..." means a 455 grain conical of some sort. 90 grains of FFg is self explanatory. Boomer is shooting a load that is stiff but not unheard of for such a rifle. If you insist on using roundball in a fast twist, you will need to load down to miniscule amounts of powder.

Fast twist and conicals with a good amount of powder are accurate and used for hunting and target work. Slow twist is for round ball. I am currently designing a build around a 45 caliber, 1/120" twist barrel. I intend to load round ball and 150-200 grains of powder. A similar rifle and load was used by the Brits for hunting. It increased the range quite a few yards by flattening the trajectory. I only wish I could have found a similar twist in 58 caliber instead of the small bore 45.
 
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Pacific Rifle Company makes (or made if they are OOB) some beautiful underhammers.
http://pacificriflecompany.blogspot.com

Pryor Mountain Bill wrote a book on making locks.
One of them was an underhammer.
Very informative.
I would think making an underhammer rifle would be one of ML gunmaking's easier projects.
--Dawg
 
Thanks folks, lots of good information.
Strawhat, is there any literature on the rifle I have, how do you know that the twist is 1/18. Where can I get conical bullets to try. I'm hoping to use this piece for whitetails, if I can hit anything with it. 455 gr bullets at a reasonable speed should be adequate.
Where can I get more info on loading conicals.
Thanks again all for the info, not too much out there that I've been able to find.
 
Those H&As usually have 1:66 twist which is perfect for roundball.

It's easy enough to measure. Do a Google search for the details but basically if you take rod with a jag and a tight patch (like you would use to clean and lube it) and put it all the way in and let it turn with the rifling you can figure it out. Usually people let it go half way around or a quarter of the way around and then measure how many inches of rod came out and multiply by 2 (for half) or 4 (for quarter). Do it a couple of times and average and you'll get close enough.
 
crgfrs said:
Thanks folks, lots of good information.
Strawhat, is there any literature on the rifle I have, how do you know that the twist is 1/18. Where can I get conical bullets to try. I'm hoping to use this piece for whitetails, if I can hit anything with it. 455 gr bullets at a reasonable speed should be adequate.
Where can I get more info on loading conicals.
Thanks again all for the info, not too much out there that I've been able to find.
Click to expand...
I have no idea what the twist of your barrel is. I was going from the information you provided re: boomers load.

A tight patch on a ramrod will tell you what your twist is. In 45 caliber, 1 turn in 18 to 50 inches is usually some sort of conical. 1 turn in 60 or more, usually indicated a patched round ball.

And yes, a PRB in 45 caliber will put a deer in the freezer. I prefer a larger diameter PRB but the 45 is the smallest I have used. With as much powder as will still allow me to hit into 3" at 100 yards.
 
Ok, and thanks all,
I did check the twist rate, about 30" for a half turn, 1/60. Hope to get out this weekend and try it out.
Thanks again
 
1-60 twist = PRB. Use the thickest patch that will allow you to seat the ball into the rifling w/o deforming the ball. Try FFFg and try FFg both - see which the gun likes. Start with an amount equal to the caliber with 3Fg and try about ten percent more with the 2Fg. Go up in 5 gr. increments.
 
What Pete said with the addition of "...and stop when you hit 90 grains, the accuracy goes to hell, or your shoulder hurts, whichever happens first."
 
Ok, and again thanks for the info,
I got a box of .45 round balls, (.457) a the local gunshop. I think that the diameter of the balls is a bit too large. The gun came with a round ball mould and the balls that I purchased seem oversized when placed in the mould. In addition when I place a ball in the muzzle, it seats about 1/2 half way, and will not leave much if any room for a patch.
The gun also came with an extra cap nipple. The one installed is larger than the spare. The spare takes a size 11 cap, the one on the gun is larger.
Anyway, I planned to shoot/play with it tomorrow.
Should I try to use the balls I have, or get some of a smaller diameter?
Any idea what size caps the nipple installed on the gun takes?
I have both 2f and 3f on hand.
Thanks in advance
 
crgfrs

Try .440 (or .430 if you can find them) round balls. .457 balls are for a 44 revolver.

#11 caps should work

SC45-70
 
Please re-read the second paragraph of the second post.

"For a .45 the ball size would be smaller, not larger (it's larger for cap and ball, which this isn't). Those H&As often had kind of undersized bores so you might want to measure it directly if you have a way to do that. Otherwise get some balls in the .43-.44 range and see what works. It's also a good idea to get a couple of different patch thicknesses and see what your gun likes."
 
Nipples

That larger nipple. How much larger? If it is about 1/4" diameter at the top (where the cap would go) then it is for a musket cap. It is not uncommon for a shooter to use a musket cap in place of a #11 cap. Larger, easier to handle when it is cold. Mostly unnecessary though.
pete
 
Got some .440 balls and they seem to fit much better. I also got some .015, and .018 patches, so I think I'm ready to go on that end. However, the nipple on the gun is large, about 1/8 of an inch, probably not a musket cap though, thanks Pete, but still bigger than an 11. What I don't have is a nipple wrench to remove the current large nipple on the gun. I really don't have anything in the toolbox that might work, that I'm aware of. Should have picked one up last week. Guess I'll have to shoot something else today.....
Thanks All
 
I have the same rifle. It has a roundball twist, 1:56 IIRC.

Use a .440 roundball with a pillow ticking patch. 40 to 45 grains of 3Fg is fine for paper punching out to 50 yards.
 
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