Going Off The Deep End
 

For several years I've had an idea in the back of my mind to build a striker fired drum and nipple caplock underhammer rifle that could mount interchangeable barrels.

Recently the itch became unbearable. So I sat in my man cave with a Scotch, my pipe, some paper, pencils and a ruler, and began sketching the design that had been bouncing around in my head.

I have a Browning 1885 45-70. I like its lines. I like the shape of its breech. I like its stock. So that's what I used as the target for how my fantasy gun would look.

Here's what I came up with.








I am going to build this sucker. With any luck you will be seeing a post on the final results in a month or so. (Sure hope I don't have to report a failure. :s10: )

A few features:

1. The breech will be cut from a block of 3/4" thick steel and will have removable side plates cut from 1/8" thick sheet steel.

2. The striker will be cut from a 3/8" hex bolt. The front face will have a nipple cup. The rear section will be hollowed to reduce weight. It will be powered by a coil spring and cocked by a knob protruding from the right (or left) side plate.

3. The drum for the nipple will be fabricated from 3/8" steel hex bar.

4. The barrel will have a permanent 1" long breech plug that is flat with the rear of the barrel. The rear half-inch of the plug will have a 1/4" threaded hole for securing the barrel to the breech with a one-inch long 1/4" hex bolt.

5. The trigger will be adjustable.

Assuming the prototype works, multiple barrels will be in its future. They can be octagon or round, straight or tapered, and of any caliber or gage. The breech face would work for a barrel as large as 1 & 1/8" across the flats and as small as 13/16" across the flats.

Wish me luck.

Looks like your off to the right start. Good scotch and a good cigar always helps me.
good luck with your build.

Crap Semi! I always thought your pool was drained and now we find you a DaVinci in buckskins!!!:biggrin::lolabove:

Good luck with your build!

HA

Semi it really looks great. Take a look at this link and you can see an underhamer with a profile extremely similiar to yours. I think this style of receiver is quite natty.

what are you going to do about a safety?

http://www.longrifles-pr.com/actions.shtml

very interesting concept. Good luck building it.

Yeah Dutch, I'm familiar with those actions. Actually, I'm a fan of the H&A style underhammer and have one. Their simplicity is a thing of beauty to me, though most people think they are odd, ugly, or both. People don't think of underhammers as "traditional" firearms. But the underhammer percussion gun is a classic American invention dating back to the early 1800's.

There's nothing real practical about what I want to build. I just want to do it, dammit! If it works it will probably be the only striker fired/drum and nipple/adjustable trigger/changable barrel underhammer in the world today. :s2:

As far as a safety goes, it won't have one at first. I do have an idea or two for a safety but will deal with that after the gun is built and proven (hopefully) to work OK. Anyway, the face of the striker will not be in contact with the cap when the action is not cocked, so it should be totally safe in the uncocked mode.

Semi, it sounds really fantastic. I cannot wait to see the pictures. Maybe you till be the next Doc White or Tony Knight!

Can't wait to see it.

The nipple, drum and striker action are very similar to the
Pedersoli Carleton underhammer target pistol.
The Carleton has an extremely fast action with an exceptionally
light trigger pull.

It's the 3rd pistol from the bottom on this page:

http://www.cherrys.com/ped_pist.htm

Wow. Thanks for that link arcticap. I've surfed the Pedersoli web site in the past but don't recall seeing that pistol. It's neat.

I did a little on-line research on the Carleton underhammer. It uses the trigger guard as a spring to drive the action like the H&R and several others, and was patented in the 1850's. Just goes to show that there's little that's completely new in this old world.

I found a good article on the Carleton that has great pictures and some with the barrel/action out of the stock. Unfortunately, you can't see how the trigger mechanism works. The article is linked below. The action pictures are on the fifth page.

http://mp510sd.weebly.com/uploads/4/...i_carleton.pdf

Here are a link to a local(South African) chap who build his own underhammer rifle.
http://whitesmoke.co.za/powwow/viewtopic.php?t=9789

Very neat. I have a 1830 underhammer that uses a drive pin to change barrels and fires through a nipple directly into the barrel like an HA in fact it was made under that original Patton. it fires as dependably as a good inline and is a very accurate PRB rifle there is only two moving parts. It originally belonged to my wife who died in 2001.

Semi - very interesting concept. Good luck. I do have one thought though. If this rifle is going to have replaceable barrels might I suggest two alignment pins in the receiver that line up to recesses in the barrel so mating of all barrels will be identical and hammer/nipple are in perfect alignment each time a barrel is changed. Or a single horizontal running pin that goes through the receiver and through a notch/hole on the barrel.
Once this sucker is done I will be honored to have a sample for field testing. I would like a .45 with a 1:30 twist and a .50 with a 1:24 for validating accuracy, functionality, and ease of use.

What a coincidence
 

Semisane,
You found the PDF file about the Carleton that I uploaded.
I had forgotten all about posting that.
That PDF was forwarded to me by the owner of a used Carleton that I had purchased. Then I uploaded it to the Weebly website for long term storage. :lolabove:

That looks like an awesome idea. I really hope you go through with building it and post regular (and detailed) updates.
Good luck.

Thanks for the link Wildeboer. I'll give it a try.

Pictures Lee. Pictures.


I had considered that Bronko. But concluded it won't be necessary. It should be a simple matter of aligning the nipple with the striker when tightening down the barrel. I don't think it will be able to rotate upon firing after it's tight. An alignment pin can always be added if it proves to be necessary in early testing.

That's a good idea Bronko. Tell you what, why don't you talk to Doc White and have him make the two barrels for slip fit conicals. You can give him your credit card number and have the barrels shipped to me. I promise to send the gun to you for testing one day. Really I do. Really. :s2:


That's hilarious Arcticap. I am continually amazed by the power of the Internet. Research that once took days in a library and would be likely unsuccessful now takes seconds sitting at home.

Semi, that's not a full drawing of the trigger mechanism... is it? How about insetting the breach end of the barrel about a quarter inch and add an alignment mechanism there? I would also use a larger diameter mating bolt if at all possible.

No UC, the drawing only shows the three main contact points, not all of the details.

I want the barrel against a flat face so I can use a variety of barrel profiles and sizes. If it works as I hope I expect to have 1" and 15/16" octagon barrels, probably a round barrel or two, and even 20 and 12 gage shotgun barrels.

Yeah. That's one feature that worries me a little. I went with the quarter-inch for two reasons; there needs to be enough clearance between the hex head of the bolt and the top of the breech block to get a wrench on the bolt, and the quarter-inch bolt better allows for smaller caliber barrels. It can always be modified if early testing indicates a larger mounting bolt is called for.