10 gauge Flintlock double shotgun help

[Pntbll499]

I picked up a copy of “Recreating the Double Barrel Muzzleloading Shotgun” a while back and I was hoping to use it to convert a cartridge barrel to a muzzleloader. My issue is the typo for tap size on 10 gauge as 10 gauge barrels are what I’ve found. Does anyone have experience with this in a 10 gauge I was wonder if a 15/16-12 tap would be what the author meant, but I’m wondering if the threads will cut too close to the exterior diameter of the barrel. Hopefully someone out there may have some insight not sure I want to ruin perfectly good barrels if it’ll still require me to end up going another route for this project.

[Bob Roller]

There are differences in breech loading shot guns from antiquity.I have heard old men talk about having what they called a "cannon breech" double barrel and that means THICK chamber walls.I have owned 2 of these.One was an English gun I got from Bill Large and the other was a Colt and both had the heavy breech.Get an accurate measurement with precision tools on the diameter of the chamber and then see if the thickness of the barrel is at least .187 (3/16) of an inch in thickness.Are these barrels twist or Damascus or something from the modern era?
The old men I mentioned were old when I was a teen ager and I will be 86 on he 27th of this month.
Another thing is extractor cut out areas and whatever allows the gun to be opened to reload.There's more to this change over than just the threads for breech plugs.
Bob Roller

[Pntbll499]

The biggest issue is honestly the breech plug threads shortening the chambers to allow for the breech plug as described in the book will take care of the extractors and the pivot for the break open they’re honestly the least of my worries and the easiest issue to handle. Barrels are fairly modern and no damascus or twist to worry about not 100% sure on age but they’re a blued steel maybe from what guys call hardware store guns, it has a taper from the extractor breech all the way down the issue is the difference between the chamber and the exterior near the forceing cone is .165” and .170”. One chamber is .850” the other .855” the exterior measures 1.020 near the cone so I am short of the .187 down near the forcing cone and if the tap cuts full depth there I’d maybe have .060 according to the math and a cross section Of 1in pipe with an .850 ID. That left .050-.045  at the thinnest point but that OD was .020 undersized from the barrel.

[Mike Brooks]

10 ga. barrels don't make attractive flint double guns.

[Daryl]

It'll be a bit wide through the front of the locks, is all.

[44-henry]

I would look for another set of barrels, 16 or 20 would be better and if you are going to the time and trouble to build it I would try for Damascus.

[Mike Brooks]

I would look for another set of barrels, 16 or 20 would be better and if you are going to the time and trouble to build it I would try for Damascus.

What he said

[Pntbll499]

I would look for another set of barrels, 16 or 20 would be better and if you are going to the time and trouble to build it I would try for Damascus.

These barrels took long enough to find most of whats available out there is sketchy looking, and heavily rusted or expensive as it is a desirable barrel set off a collectible brand shotgun, as far as damascus goes I have no desire to restrict the search criteria more, I’m fine with just blued steel when its all done and over with I’m not looking to make a gun that looks like a period or original example with damascus barrels. It was between this 10 and a heavily dented 12 and I was hoping this would work, and it still may. But local shows seem to offer very little and most online stuff is just more money than its worth for something to hack up.

[Pntbll499]

10 ga. barrels don't make attractive flint double guns.

You’re a man of many words with so much to offer in conversation…

[D. Taylor Sapergia]

Mike is correct.  If you do decide to go with those 10 ga bbls., be sure to make recessed breeches, to keep the stock as skinny as you can.  Slapping locks on the outside of a pair of 10 ga bbls will make a gun that is nearly 3" across.  Try to get a nice wrist out of that situation!  And find a piece of good walnut to match...very spendy.

[Mike Brooks]

10 ga. barrels don't make attractive flint double guns.

You’re a man of many words with so much to offer in conversation…

Thanks! I always try to help a feller out.

[44-henry]

You seem overly concerned with expenses. By the time you get a pair of appropriate flintlocks, acquire suitable wood, and figure in the time necessary to build all the other stuff you won't likely be able to buy, it is going to add up to an expensive project. In short, the barrel is probably the least of your expenses. Starting with the wrong one seems foolish.

Also, since you are new to the forum you should know that both Taylor and Mike have built these guns. If you are serious about building one you should listen carefully to what they are saying.

[Pntbll499]

Its not like Mike has said anything of any value other than don’t do it with little reasoning or information, or advice, Taylor and Bob have had about the best info contributed so far. I’ve built flintlocks I do understand the cost of things but when the value of a barrel set online is nearing $180-250 well at that point I’ll just buy new and build a single barrel fowler and take out all the guess work. Pickings have been rather sparse from what I’ve found and I’ve been trying to do some digging for a few years now, if I can build these and fond something better along the way I can always build another if better barrel options pop up.

[Clark Badgett]

It's not like old sets of barrels are rare. Just in the past year I have acquired 2 sets and haven't paid much for them either. Learn to scour your area and not be so completely reliant on the internet.

[Daryl]

This is a 12 bore. A 10 will likely be close to an inch wider.

[Pntbll499]

It's not like old sets of barrels are rare. Just in the past year I have acquired 2 sets and haven't paid much for them either. Learn to scour your area and not be so completely reliant on the internet.

I’ve been scouring for 3 years now unfortunately most of the local shows gun shows haven’t turned up much, given the issue I’m running into with thickness and odd threads I’d love to find another set this guy had 2 sets a heavily dented 12 and this 10gauge set that I picked up for $40, but I haven’t really saw much else locally, gun shops in my areas of search are even worse than the shows. It seems odd cause back before I had this project in mind there was a guy at most shows who would have doubles and parts for fairly cheap all the time but I’ve not saw him in years and guessing he’s no longer dealing in these things. As I’ve said I’m still looking but little else is turning up. I’ve had these on my bench for close to a year while I’ve kept up the search but decided to see if these could be made to work.

[Pntbll499]

This is a 12 bore. A 10 will likely be close to an inch wider.

Was this 12 constructed converting an old cartridge gun? Thanks for the pics and do you have a measurement across the widest portion.

[Pntbll499]

Mike is correct.  If you do decide to go with those 10 ga bbls., be sure to make recessed breeches, to keep the stock as skinny as you can.  Slapping locks on the outside of a pair of 10 ga bbls will make a gun that is nearly 3" across.  Try to get a nice wrist out of that situation!  And find a piece of good walnut to match...very spendy.

The width may be the nature of the beast and as I’ve said I’ve continued this search and have still been coming up short for other options, although I don’t think the sources I’ve looked into for wood, would be to much of a pain to find what I’d need I haven’t fully asked them for info yet as I’m not even sure I can get this up and running

[martin9]

After reading this thread I looked for old double barrels on ebay. One really nice set of damascus 12 ga barrels for under $200 and a couple others, same price or less but not as nice.

[Mike Brooks]

I have bought old percussion German shot guns just for their barrels. They usually have bores somewhere around 20 bore. You can often find them for 400 dollars or so. Strip the barrels out and you're ready to go.
I don't often go into great detail answering questions  anymore  as it's  a waste of time. People always end up ignoring  my information and doing things the way they want to.

[Hudnut]

Here are a couple of antique gunsmith made doubles.  Both used a pair of India Pattern (3rd Model) Brown Bess barrels.  About 11ga.
Gun in the top picture was originally flint; converted to cap.  Gun in lower picture is original percussion, with back action locks.  These are big guns.  First has 37" barrels, the second, 39".  They weigh about 14 pounds.  I assume they were made as waterfowlers for market hunting.
The width across the breeches is remarkable.  Neither used a recessed breech.  These guns illustrate the desirability of smaller bore barrels for flint doubles.  With heavy barrels, width is a real issue.
 

[Clark Badgett]

I have bought old percussion German shot guns just for their barrels. They usually have bores somewhere around 20 bore. You can often find them for 400 dollars or so. Strip the barrels out and you're ready to go.
I don't often go into great detail answering questions  anymore  as it's  a waste of time. People always end up ignoring  my information and doing things the way they want to.

Around these parts old cheap Belgian rear loaders are fairly common, even the occasional lower end English offering. They almost always have busted stocks held by the craziest of manners. Not worth saving in their current state but the barrels can be in good shape if you examine them thoroughly.

[Austin]

Im with Mr Brooks, ive got a Nocked breech 20g thats like sighting down a 2 by 4; a 10g would be like a2x8!

[D. Taylor Sapergia]

I built the shotgun Daryl illustrated here from barrels I sourced by buying an antique double 12 bore breechloader.  I pair $75 CDN for the gun at a rendezvous.  Using Brockway's book as a reference, I cut the breech end off, threaded the chambers 7/8 x 14 tpi and made the plugs on the lathe.  I also cut off about 3/8" at the muzzles as the barrels were paper thin out there.  I used L&R's Bailes locks, recessed the plugs and altered the pans and plates to work.  I bought my wood from my old boss at Robinson's Firearms Mfg and the first stick he sent me was not thick enough, so I returned it and bought one that was lots thick enough.  It is a good piece of English walnut as you can see from the photos, but it cost me $500 CDN.  So what I saved in the barrels, I more than made up for with the wood.  But I do not regret it...that English is wonderful to work with and is spectacular when finished up.
Making a double flinter is a great project, and I hope you won't be discouraged as you go along.  It is likely that someone here will have a set of barrels that would be better suited for the project and is willing to sell them to you.  I have sold around five pairs of barrels here myself.  I'll see if there is anything suitable in my rafters this morning.  And I'll take a measurement of the widest part of the gun through the locks.

[Daryl]

SxS 12 bore.








SxS 20 (I think) bore by Cody Tetachuk.