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.

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.

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.


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.