Underhammers

[rodwha]

John Taylor built and posted a pic of a nice looking 12 ga underhammer that brought up a few questions that brought on a few more.

First off I've seen them posted a few times on various forums but had always noticed them being smaller calibers (<.50) and percussion.

In his thread I had redirected (sorry) he mentioned that they actually make them in flintlock (and were originally), and actually fire faster.

I'm curious how the powder stays in the pan. Ultimately I'd assume the frizzen is hard to move making it a very deliberate action to move it. However it seems that would also make it near impossible for the flint to strike the frizzen and throw the sparks into the pan.

I'm also curious what makes an underhammer ignite faster.

[StolzerandSons]

If you examine any flintlock underhammer or sidelock you will see that the Frizzen is held closed by a spring. You would think that gravity would let the powder fall out once the flint starts to hit the frizzen but it actually happens so fast that the powder from the pan ignites and the flash blows up into the flash hole before it can drop.

Underhammers aren't necessarily faster they just tend to be because the flash hole is a straight line into the powder unlike most caplock(Sidelocks) that have a 90deg turn between the nipple and the powder. Flintlocks(sidelock) are also usually a straight hole into the powder so they are also usually very fast compared to caplocks, If they are properly tuned and working like they are supposed to.

[rodwha]

I'm fairly ignorant about flintlocks as well. I have just one caplock rifle with the intentions of a few barrels to drop into it along with a small bore small game rifle.

But these guns have ignited a curiosity of flintlocks and the history behind those times. One day I'll have a flintlock as well, likely a common one used by us against the British.

[pietro]

I'm curious how the powder stays in the pan.

I'm also curious what makes an underhammer ignite faster.





Here's a slo-mo video of firing an U/H gun: https://www.youtube.com/watch?v=IXyybh-llLk


Underhammer percussion guns have a fast(er) ignition because the short ignition channel goes directly to the powder charge w/o any turns, and the action is as simple as possible, having only 2 pivot points (the trigger & the hammer).

U/H flintlocks, however, usually have ignition a bit slower than a conventional rocklock.

In an underhammer flintlock, the powder is sitting on the top of the frizzen ( in reality the underside of the frizzen in the position we normally think of).

When the flint strikes, moving the frizzen, for a few micro-seconds the powder is still hanging there in mid air - or is barely starting to separate and fall.

The spark travels very fast, igniting the powder charge, whose flame reaches the touch hole.

The remainder of the ignition occurs like any other flintlock - if it misfires, you will obviously have to re-prime.

Here's a post by an U/H flintlock builder, where he explains what he did: http://underhammers.blogspot.com/2009/05/yes-another-underhammer-flint-pistol.html

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[rodwha]

Very interesting. You mentioned a spring that held the frizzen in place. I noticed that the frizzen stays open upon being struck and doesn't rebound.

[StolzerandSons]

201067
201068
If you look at the frizzen and it's shape you can see that it is actually an upside down "v" shape(even if it has a roller) and that "v" shape allows it to hold it's position when fired(no rebounding closed). Think of it like trying to tip a triangle over.

[oldracer]

I have a pair of under hammer rifles, both are percussion. I bought one that is a 58 caliber, 1 in 48 twist barrel that shoots either round balls or minis out to 200 pretty well. I built one from the parts I sourced from Pecatonica River with a 1/18 twist Green River barrel and it shoots fantastic out to 300 yards with 540 grain Creedmoor grease groove bullets, 90 grains of Goex FFG and a 209 shot gun primer adapter. I have tang sights on it and I use a rest on a bench. For both barrels when I pull the nipple or the primer adapter there is slight build up of hardened powder with a small hole through it that fills up the threaded flash hole? I am not sure if this is normal but they shoot well except for off hand!

If you are interested I'd suggest talking to the folks at Pecatonica and getting one of their "under hammer kits" and put it together. Nice thing is there is very little barrel channel to have to scrape out and they drill and fit the pinch bolt. I have a couple pictures of mine on here I think?

[big bore 99]

I read somewhere that it was a test of a quick flintlock to be able to fire it upside down. I have an old .58 percussion that shoots real nice.

[RU shooter]

If your interested in the principal of an underhamer but want it to look a little more conventional LR sells what it calls a mule ear or side slapper lock . Same principal cap is fired in a straight line into the barrel

https://www.trackofthewolf.com/Categories/PartDetail.aspx/791/1/LOCK-LR-2500

[bob208]

I have 5 under hammers plus one extra action I am thinking about building a .38 out of. all the others are .45. I have shot them in matches for years now. the cap locks are very fast and trouble free.
also they are right and left hand all in one rifle.

[Bmi48219]

I recall back in the 1960's a company (Hopkin-Allen?) made percussion under hammer rifles & a 'boot pistol'. They were advertised in several shooting type magazines. Think they were made in USA. Anyone have one?

[bedbugbilly]

I don't have a flint under hammer but I do have two percussion under hammers and have owned several others through the years. I like them due to their simplicity and when my right eye started giving me problems, I had to start shooting left handed - the under hammer was perfect for that change.

Too many folks think that there is a "mystery" about flintlocks. If you are one of them, I encourage you to shoot one if you have the opportunity as you'll be hooked. A well tuned lock which throws a good shower of sparks in to the pan along with s correctly positioned vent hoe will give you almost instant ignition - not a "lagging" ignition that most folks who don't shoot flintlocks think they have.

As already mentioned, a good flintlock lock will have a tight fitting "water proof" frizzen that when closed, snaps in to place.
Whether it is upright or down below, it will fire just fine. A good example would be a swivel breech over/under flintlock. The frizzen and pan for the bottom barrel would be upside down until the top barrel was fired and the barrels swiveled, ready to shoot what was the bottom barrel.

I like my under hammers because they are simple, the nipple is threaded right in to the barrel so there is no flash channel of a drum or bolster. If you want the same type of ignition - i.e. the nipple screwed directly in to the barrel but you don't want an under hammer - you have the option of a "mule ear" or "side slapper" lock. The lock is side mounted just like a conventional lock but the hammer swings sideways and tricks the nipple which is threaded directly in to the barrel. L & R is not making the mule ear locks and they are really nice. I just got one to use on a build. You can use either a single or a double set trigger on theirs.

[bob208]

all 5 of mine are h&a.

[John Taylor]

Took in an older H&A today, looks like it has never been cleaned. another project.

[charlie b]

http://underhammers.blogspot.com/

My favorite. Look about halfway down this page. The Ultimate Underhammer. That may be my next build.

[John Taylor]

http://underhammers.blogspot.com/

My favorite. Look about halfway down this page. The Ultimate Underhammer. That may be my next build.

Roger said he is moving on to new projects and will not be making under hammers. I guess we are both getting old but I still need to make a living so a few under hammers get built every year, between other jobs. I have an original that I hope to get going again. I have not seen one like it before. It is unusual because it has a piece of sheet metal for the forearm. This is formed so it has a channel for the ram rod and is soldered to the two lower side flats of the barrel. The but stock has a lot of figure but may not be reparable. It has a crescent brass butt plate and a grease hole on the right side. I was surprised that the rifling look usable except for the last inch. The breach plug and tangs are forge welded and will be discarded, threads are not a good fit to the barrel. What will make the restoration difficult is that I did not get the hammer, trigger or springs. There is no makers name and it does not match any that I have found in books.

[Ballistics in Scotland]

I read somewhere that it was a test of a quick flintlock to be able to fire it upside down. I have an old .58 percussion that shoots real nice.

Ah, at last somebody said it. Not that anybody would want to, but for duelling pistols or shotguns intended to shoot flying, the speed of ignition was crucial, and closely related to the same qualities that made for the nearest possible to certain ignition. A lot of work by the best, highest-priced gunmakers went into both. Of course the best geometry of the metalwork was still dependent on how the user set his flint, and priming with a special extra-fine powder was a big help. If an underhammer flintlock had these qualities it might work extremely well, but if it was slow it had better be the normal way up.

Musket locks were designed for ruggedness and cheapness. I've never thought the smooth-bore military musket and loose-fitting ball was the piece of folly some say. March even a depleted battalion out of the smoke to within thirty yards of another struggling to reload fouled pre-Minié rifles, and you might as well have an unopposed minute machine-gunning them. But with the trouble and cost of getting that battalion to the battlefield, it seems like a fool's economy not to copy the best civilian lockwork, and have another 5% of the gunads going off. The military standard in a duelling pistol could leave one individual with 100% of a serious problem.

Some waterfowl shooters, who did a long, wet stalk with a very big gun, disliked the first percussions because they didn't alarm a sitting flock like the flintlock did, and you got more if they got a little off the ground. That argues that these guns had a lot slower than state-of-the-art ignition. In fact plenty of their locks were simply spinoffs from military musket contracts.

Long ago I sandwiched some black powder between two sheets of wire gauze, and ignited it by a saltpetre-impregnated fuse, tape instead of string. I only did it once, so it isn't a conclusive experiment, and heat from very brief combustion mightn't behave like heat from a lasting fire. But a piece of paper an inch above much more charred than one an inch above. So it suggests that an underhammer flintlock might work very well.

The flash from a percussion cap travels almost inconceivably fast, so I don't believe the cap-to-powder distance matters. Changes in the direction it must take might, especially if fouling built up there. Track of the Wolf used to recommend their larger diameter breechplugs as permitting a single diagonal hole from powder to the little cavity under the nipple.

The underhammer percussion gave the face and eyes unrivalled protection from the flash and fragments of cap. So it fits pretty well at opposite ends of the spectrum - light, simple buggy rifles, possibly for someone who wasn't a regular firearms user, or long-range match rifles with elongated bullets, which generate enough pressure to lift the hammer. They really need the cap to be a tight fit on the nipple though, since if it falls off just once, it is going to be on the shot of a lifetime.

A boxlock percussion gives just as short and straight a flash channel as the underhammer, and is least vulnerable of all to damage, but interferes with the sighting. But this shouldn't be a problem with a double barrel. I've always thought there was an role for a lock like my Austro-Hungarian Werndl, a sidelock with the hammer inside the plate, but I have never heard of this being done in a civilian application, or a muzzle-loader.

201201

[jdfoxinc]

Numrich arms made H&A style under hammers in the 60s. I obtained one through my ML shop but didn't get a chance to shoot it befor it was damaged in the fire. My gun Smith is restoring it.

[oldracer]

If you check Pecatonica River's website they list two under hammer "kits". The H&A looks like what most people think of and the Allen has a slightly different breech area. The Allen can also be adjusted for trigger pull while the H&A can not it appears. I have mine set to 2# like the pull of my Pedersoli Gibbs. You can get any barrel with those folks and I was able to find a Green Mtn. 1 in 18 45 caliber and so far shoots about 1 1/2 MOA out to 200 yards with the tang sights. I asked them to install the barrel and also cut the necessary dove tails for the fore end and globe sight. Note that pretty much any barrel could be used on a rifle like this. Here is a picture of the middle part of the rifle.

[Edward]

Sure do and as I understand the H+A mod 32 that I sent to johnson1942 for rehab will be coming home with new wood and upgrades due to rogers magic ,will post photos upon arrival /Ed 201624201625

[dondiego]

I just acquired an H&A underhammer in well used condition. It appears that the barrel retaining pin is drifted out from right to left one way only. Can any of you knowledgeable UH guys confirm this? I have beat on it pretty hard with a plastic mallet and the pin has not budged. Any ideas on a removal method?

[oldracer]

From what I have read, the H&A rifles used a pin and also set screws. When I got my 58 caliber H&A I talked with my mentor and he said there was no reason he could think of to remove the barrel unless the insides are pitted so bad the gun will not shoot well at all. For cleaning, I use a spare nipple I drilled out some and then screw it in snugly with some tubing attached to it. If you have to pull the pin one side should show larger than the other with a magnifying glass, drift from the small side.

[bob208]

yes it is a tapered pin. I have seen some come out left to right. and a others right to left. it can get confusing. some the pins are easy to see which is witch. others you will have to measure. there is also a screw in the top of the receiver that needs to be removed. but then unless you are replacing the barrel there is no need to remove it.

I use the tube on the nipple to clean mine it has not failed me yet in 20 years and I don't think it will.

[dondiego]

Thanks for the replies. I was planning on totally refinishing barrel, receiver, and wood so wanted the barrel off of the receiver. I also have another barrel (.45cal) that I would like to be able to interchange with the receiver. It is soaking in Kroil now but I am sure not able to get that pin to move! If it doesn't want to come out after the Kroil treatment I will try some heat. Any other suggestions would be welcome.

[bob208]

I have a spare action I was thinking of building a switch barrel rifle on. the underhammer action is a great action for such a project.

[dondiego]

I am left handed and my father bought my first UH rifle for me when I was 15 years old. UH's are great for lefties and I have always had a place in my heart for them. I still have my original from when I was 15! It is in .45 cal and the most recent one is a .50 cal. I built a .54 cal from a Pecatonica River kit in 2013. I am working on getting a .36 now too.

[Maven]

dd, After reading your posts, I went to the Numeric Arms/Gun Parts website > Hopkins & Allen. There are 59 pages of parts, but I was hoping to find an exploded diagram for you, but didn't have the time to search for it. You may want to look at those pages...just in case.

[dondiego]

Maven - Thanks for your input. I visit the Numrich Arms site on a daily basis and regularly check the H&A page and check for parts for the UH rifles and I also need a part for my H&A UH Boot Pistol I also visit the Enfield P-14 and the Colt 1903 page. I enjoy refurbishing old, broken, firearms with original parts when available. Have several needing parts right now.

[Hanshi]

I still have my H&A "Heritage" model .45 underhammer rifle. I bought it in the mid 1960s and it still has great sentimental value and the barrel is pristine.

[ogre]

Before Roger built the Faeton he built the Zephyr. I have one of these in 62 calibre and it is still an unfired safe queen.

[Harleysboss]

Oh But Why? Take it out and shoot it, that's what they all deserve.

[ogre]

I am no longer a young man. Perhaps you would like to shoot it. With it's Forsyth rifling it's designed to shoot a patched, 341 grain, roundball over 175 - 200 grains of 2fg.

[Harleysboss]

ogre, challenge accepted! I would love to.

[ogre]

It's not a challenge. It is an invitation. I live in Vancouver, WA.

[Harleysboss]

Ogre, Long day at the office today. Thats a very nice offer Thank You. I'm north of you by about 2.5 hours. Hunting season is barreling down on us now. Maybe later in the fall.

[bhuch5]

dondiego- you have a pm ---Bruce H

[John Taylor]

I made several barrels with the Forsyth rifling, very narrow lands and wide grooves with 1/4 turn in the length of the barrel. The whole idea is easy loading and a very high speed ( for black powder) round ball. The heavy powder charges will develop a flinch in no time. Roger said a 3" group is about as good as you can get, more than likely minute of deer size. I think I still have a couple on the shelf if someone really wants to go that way.

[mazo kid]

I am a late-comer to black powder shooting as far as some others here, having started in 1972. I do remember the TC UH pistol, cost was a whopping $36.00 at that time!

[dondiego]

TC Underhammer? Do you mean H&A?

[charlie b]

If you want one then this would be a good choice. I only wish I had the funds available now.

https://www.trackofthewolf.com/Categories/PartDetail.aspx/492/1/AAQ-229

[Edward]

Speaking of underhammers ,I got mine back from johnson 1942 last week and it looks great ! If the monsoons stop will shoot some squirrels ,(while they stop to admire the gun) I might be able to get some . 203276203277203278203279203280203281

[Multigunner]

First BP muzzle loader I ever fired was an underhammer target rifle in .58 caliber that was loaded with a 1000 gr two piece slug, hard lead alloy nose and softer paper patched body. Charge was over 300 gr.
I shot a locust post with it and turned half the post into tooth picks.

[oldracer]

Great finish on that under hammer! Rogers sure has a way with lacquer and the polishing process to bring the shine out. I bought a rifle he made several years ago and everyone at our San Diego range was amazed by the way it looked. I finally contacted Roger and he gave me all the steps and what products to use and it generally takes me 3 weeks or more to get a finish done (4 rifles so far). He made a sticky on how to do this for the site here.