Hopkins & Allen Underhammer


Ray P
January 17, 2011, 08:22 PM
Just bought a .36 H&A underhammer rifle, and since Numrich isn't making them anymore, there aren't many places to go for maintenance & cleaning tips for these neat guns.

I've searched a number of gun forums, and read through all pages of the Underhammer Society blog, but haven't found answers to a couple of questions...

1. Do you generally dismount the barrel from the half-moon "receiver" for cleaning, or is it better to just use a siphon tube? OK, I know it is not a true receiver, just couldn't think of a better name for that block of metal holding the barrel, stock bolt, and trigger group pins together & in alignment.

2. Are the nipples long-shank, 1/4-28 or metric, or some other unique design? The shank looked kinda long, and the threads don't match up to a 6Mx0.75.

3. Why are Hot-shot nipples mentioned as something to avoid with underhammers?

4. My 3rd Edition Blackpowder Loading Manual doesn't show the .36 H&A, and I don't have the original owners manual. Can I assume 30-60gr FFFg as a reasonable load range for patched round ball? Oh. Using .350"D rb & 0.015" patch.

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January 17, 2011, 09:14 PM
mine is a .58, but in answer to one of your questions, I have never dismounted the barre...it's just not nessesary. After a few passes with a bronze brush to loosen up the crud, I pull the ramrod up and down with very hot, slightly soapy [dish soap] water in the barrel, and a bit of rag around the jag, and it acts as a sort of piston.Do the same with plain hot water as a rinse. Wait a few minutes for any water to dissapate [it won't take long if the water was hot enough] and wipe down the inside of the barrel with a slightly oily bit of rag on the jag, and a wipe down of the outside metal with a paper shop towel with a spritz of WD40 on it, and I'm done.

January 17, 2011, 09:54 PM
Mine is a .45 cal. I haven't dismounted the barrel simply because I haven't figured out how. I use the siphon tube to a container of hot soapy water and then use a patch on the jag. I use some more patches to dry it. I use bore butter finally but there are other products if you like.
There was a longer shank nipple on it when I got it but I was getting misfires so I changed to a shorter shank and that helped.

Ray P
January 18, 2011, 09:53 AM
Thanks for the responses.

Siphon tube it will be :-) Those three setscrews were looking a bit intimidating, anyway. Not quite as simple as the hooked breach and wedge pin of a TC.

Came across more info while shopping for a cleaning nipple. Track of the Wolf (http://www.trackofthewolf.com/categories/tableList.aspx?catId=14&subId=171&styleId=785&as=1&PageSize=25&Page=2) stresses Numrich rifle nipples are 1/4-32. After close inspection and comparing it to known-size nipples from my TC & Lyman guns, the H&A nipple measures as a standard shank 1/4-28 thread. Also looks pretty clean & un-hammered, which makes me think the previous owner just shoved in something close enough to fit in order to trade it off. I don't feel I'm getting good thread engagement. Think I'll need to pop the forearm to give the barrel threads a closer look for evidence of cross-threading.

January 20, 2011, 12:53 PM
Don't dismount the barrel. The barrel is held on with a tapered pin through the receiver and breech plug tang. Continued driving in and out will cause it to become loose. Numrich has some parts for these.

If you must pull the barrel, look at the pin to determine which is the big end and drive out from the other side.
Nipple "should" be 1/4-28 and I can think of no reason not to use a hotshot nipple. It is further away from your face than on a sidelock.

moose owner
January 20, 2011, 08:51 PM
I have a 58 caliber H&A too. The tapered pin which holds the barrel in place is often very difficult to get out. So, most people clean the barrel while it is attached to the receiver. I pretty much destroyed the tapered pin when I decided to drive it out.

If you look at the Fire & Iron Manufacturing “H&A” Actions, they use Allen socket screws to hold the breach plug and barrel in place (as apposed to a tapered pin). Removing the Allen screws is easy, making it possible to quickly remove the barrel for cleaning (or changing out the barrel).

I modified my H&A to also use Allen screws to hold the barrel/breach plug in place. I also fitted a 12 gauge shotgun barrel to my H&A so I can shoot it either as a 58 caliber rifle or a shotgun.

Ray P
January 20, 2011, 11:25 PM
Think I read in the Underhammer Society blog Numrich changed from taper pins to set screws towards the end of production. My .36 has the setscrews, but I think I'll avoid dismounting it, at least for a while. Siphon-tube cleaning it shall be.

PapaG; you're right on the thread size; 1/4-28 it is. Did pull the forearm off today, and gave the barrel threads for the nipple a close inspection. Under the 10x loupe, they looked fine. No evidence of cross-threading, just crud in the threads where the std-length nipple doesn't reach. Chased the threads with a 1/4-28 bottoming tap, and didn't sense any problems. Maybe that brass cup is just throwing off the feel a bit.

Maybe it was in the US blog back pages, but I did see one guy cut down his .58 H&A to canoe gun length; looked VERY impressive!

January 20, 2011, 11:52 PM
I would but then that 40'' brass scope would just look ridiculous...


Ray P
January 21, 2011, 12:18 AM
Nice! Shadows at the action is throwing me off a bit; what is the one on the top?

January 21, 2011, 06:17 PM
Whitney Rolling Block .38 Short Colt Cadet's or training musket that some goober sportered.

January 23, 2011, 02:01 PM
http://i599.photobucket.com/albums/tt74/hanshi_photo/Picture0387.jpg Mine is a .45 built in the mid 1960s. While yours may be some different, I always tapped out the pin and removed the barrel for cleaning and I've had the rifle for 45 years. It still fits together as tight as when it was new. I usually tap out the small pins and remove the fore end but it is not always necessary to go that far. I recently had to (temporarily I hope) retire the rifle because it needs a new tg, which as you know, powers the trigger and hammer. I guess I need to start seriously looking for one.

January 23, 2011, 05:36 PM

January 23, 2011, 07:42 PM
My barrel is not held in place with anything. It just screws on the threaded action shaft until it butts up against the action face and the sights line up straight. Am I missing a piece on this gun? (haven't fired it yet...)

January 24, 2011, 09:26 PM
Don't know if this will be of any help here... but the barrel on my Bess and many other muzzleloaders also doesn't dismount for cleaning. What I do is plug the vent with an old fashioned match and fill the barrel full of hot soapy water from a pyrex measuring cup. Drain, repeat, drain, scrub like hell, dry, and oil. Seems to work.

January 24, 2011, 09:45 PM
@BHP Fan: Wow. I thought BlueGrouse was dead & gone.

@1776: Is your underhammer an H&A action? Got photos?

@ Goon: Been known to do it the old-fashioned way, but guess I got lazy with the hook breach :-)

January 24, 2011, 10:33 PM
The Bluegrouse site seems to still be active but nothing appears to have been added since 2004 or so?
Anybody heard from him?

January 24, 2011, 10:55 PM
Risking a highjack of Ray P's thread, but...

I do see him with a recent ad in www.auctionarms.com:


Ray P
January 29, 2011, 11:04 PM
Took the H&A to the range today, and she operates rather nicely. Got 1-1/2 grouping using 40 gr FFFg at 50 yds; tighter than the 30 gr & 50 gr loads. The patched ball dragged at a few spots on loading, but that smoothed out after a few shots. Patches looked good; no cutting or burn-throughs.

Pretty sure if I bring the right glasses with me tomorrow, I can tighten that group up considerably. Will probably try some weighed Triple 7 FFFg for consistency, too.

Oh. Got a flushing nipple for cleaning from Track of the Wolf, and that worked very well.

January 30, 2011, 08:17 AM
Triple 7 is much lighter than BP for the same energy. You must reduce your load by 15% VOLUME to achieve the same result as BP. Be careful you are not overloading when using 777. Use a volume measure.

Ray P
January 30, 2011, 02:17 PM
Junkman 01; You are absolutely correct. I just gave a short-hand description.
By volume: the Lee slide rule says (FFFg) 30gr = 1.9cc, 35gr = 2.2cc, 40gr = 2.5cc, and 45gr = 2.8cc (rounding to the nearest 1.0 gr).

I take three carded samples of each, weigh & average, and that becomes the value I store in the chargemaster for future use. I've done this for Pyrodex RS !ONLY! after Hodgdon published it is acceptable to use smokeless powder dispensers for Pyrodex. I then either build paper cartridges, use speedloaders if I'm in the woods, or bead tubes if I'm going to the range. But all this has been for my .50 Hawken or .58 Enfield Musketoon

****DON'T****DON'T****DON'T****DON'T ****DON'T****
Do not put actual black powder in a dispensing system not specifically designed for black powder!
****DON'T****DON'T****DON'T****DON'T ****DON'T****

Ray P
January 30, 2011, 02:30 PM
And a 15% reduction by volume becomes...
Lee slide rule says (FFFg) 30gr => 25gr = 1.6cc. 35gr=>30gr = 1.9cc, 40gr => 34gr ~ 2.2cc, 45GR =>38gr ~ 2.5cc (roundingby 2gr for the nearest dipper).

Ray P
January 31, 2011, 02:02 AM
Here is the H&A at the range today.

Ray P
January 31, 2011, 02:09 AM
Also, Here's a shot showing 2 of the 3 setscrews which I believe replaced the taper pin in later models

Got to say I have a lot of work ahead of me re-learning the basic techniques. This thing is very sensitive to variations in loading pressure. Just not as forgiving as a 350+ gr maxi over 110 gr RS. :-)

This is a fun gun to shoot!

December 26, 2015, 03:11 PM
I was disappointed in that noone ever said which direction you drive the tapered pin to drive it out. Normally, it's the same way to drive out dovetailed sight I thought. I heard it said "Drive it right out unless you want it left in"

Right as looking towards the muzzle with the gun top side up. been trying but having no luck.. Want to convert it to use set screws to retain the barrel.

Any help would be appreciated!

Ray P
December 26, 2015, 10:40 PM
Sorry I can't help you, Newtire. My underhammer barrel is retained by set screw, not taped pin.

December 27, 2015, 06:37 AM
"I was disappointed in that noone ever said which direction you drive the tapered pin to drive it out."

Measure each end of the pin, whichever end is the largest drive it out from the other end. When it comes to reassembling, put the skinny end of the pin in the larger hole & tap it back into place.

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