Single Barrel Conversion....

[reivertom]

Has anybody here done a single barrel shotgun to big bore rifle conversion like the double barrel conversions on earlier posts? It would seem it would be an easier job, if you could find a sturdy action to work from. I know there are already single shot rifles on the market, but not in bores larger than 45-70. I would like to have one in an old blackpowder cape gun or even nitro cape gun caliber.......just to play with...just a thought. I know it would be light, but with light loads it would still make a lot of noise and not kill the shooter too much.

[Green Frog]

The thing to remember about this kind of conversion is the pressure limit imposed by the relatively weak receiver that was sufficient for even a 10 or 12 gauge, but with that consideration you should be able to take a modern made, relatively strong 12 gauge gun and either sleeve it (like lining a regular rifle barrel) or by mono-bloc alteration of the existing barrel.

About 15 years ago, Michigan gunsmith extraordinaire Steve Durren built a schuetzen rifle (32-40 IIRC) based on a H&R Topper(??) and described his work in a serialized article in the ASSRA's Single Shot Journal. You might want to go over to the ASSRA.com website and see whether anyone can dredge up a copy of that one for you. It will at least give you some ideas of what might work.

Froggie

[ascast]

I was just looking at a combo, German, old 16ga by 11mm Mauser. The rifle barrel was bulged from an overload: I assume. People commonly use 45-70 data for any old 43-11mm type loads. It is a BAD assumption.

[rking22]

As cast, I was considering that same gun. Too bad about the rifle side, I also passed for that reason.
A single would be interesting, HR / NEF actions could do it fine, just not very elegant in appearance. If you go for it post a build thread for inspiration!

[ascast]

As cast, I was considering that same gun. Too bad about the rifle side, I also passed for that reason.
A single would be interesting, HR / NEF actions could do it fine, just not very elegant in appearance. If you go for it post a build thread for inspiration!

$1200 no negotiations, no phone, no emails. It will not shoot proper with that bulge, so 1) counterbore the front 20 " and have $300 worth of brass? would it hit a deer at 200yds? 2) rebore to 44-77 or 45-70; maybe use the brass or get a working piece at least. You now around appx $1800 for a black powder toy. Also, I understand that those old German double throw firing pins on occasion, maybe taking the hammer with it. Not for me, I think.

[Toolmaker TN]

Norman Johnson also did an article on doing the same thing on a TCR '87. Same principle. I think I may have both it and the Steve Durren article somewhere in my files. If I have them, I would be glad to send you pdf.

[elk hunter]

I've barreled a couple of 45-70's on single shot shotgun actions for a friend.

Check out you tube for "Brian shoots Cape Buffalo with 577 single shot and cast bullets".

The rifle was built by Brian on a ten gauge single shot action so it can be done.

[bdicki]

I had a TCR87 with barrels in 308, 7mm Rem mag, and 12ga slug, the 12ga was not pleasant to shoot.

[country gent]

I haven't seen any done to 45-70 or other lower pressure rifle rounds. I have seen doubles done. The builder looks for forged receiver action for this conversion rather than a cast one. What I have seen done several times is a single shot shotgun either sleeved or the barrel stub threaded and converted to a muzzle loader. Usually in 50 cal and using a 209 primer for ignition. One I seen done in 50 cal was a real beauty a quarter rib with 3 folding leafs a very nice ramped front sight with brass face.

[Ballistics in Scotland]

I was just looking at a combo, German, old 16ga by 11mm Mauser. The rifle barrel was bulged from an overload: I assume. People commonly use 45-70 data for any old 43-11mm type loads. It is a BAD assumption.

It is very rare for any kind of barrel to be locally bulged purely from an overload. Almost certainly it is due primarily to a bore obstruction. A drastic overload is much more likely to rupture the immediate chamber area.

Some American single shot shotguns were made of malleable cast iron. As in the Stevens Favorite .22, it was an adequate material for its intended purpose. But I would be very wary of using such an action without good sources on exactly what it is made of.

Good moderate-pressure double rifles used to be made on much the same technology as shotguns - i.e. case-hardened mild steel, but good mild steel, well forged to shape. Although the same metal, there may have been quite a bit more of it. The early German combination guns are an example, but the high-pressure cartridges used in some of the later ones may depend on tool steel. Rear extensions, doll's heads etc. are of sometimes exaggerated value. They mostly prevent (or fail to prevent) action rupture turning into disastrous rupture.

You do have to look carefully at the dimensions of what you have got, and know what quite a few guns look like. A boxlock takes more metal out of the action body than a sidelock, and a back-action sidelock least of all. The old-fashioned rotary grip lasted longer in big game rifles than shotguns, not because it "screwed" the barrels tight down onto the action table (more or less an irrelevance) as because it removed less metal from the action than the Purdey-style sliding bolt. The danger point in the action is fracture on a line from the breech face downwards - just where a boxlock nearly always needs to put a still more weakening screw-hole.

Leverage is much less on the action bar forward of the breech face, so it can have more of a taper in depth than most American single shotgun actions. Here is my W&C Scott 10ga, known to my friends as the Great Scott, which would surely make a good medium-pressure black powder equivalent rifle if I could spare it, which I can't. It has the 1875 to 1887 "Not for ball" marking, and is damascus barrelled, but nobody much wants to save much weight on a 10ga single, so it has a lot more metal in action and barrel than a lot of shotguns made when there was no nitro proof, but gunmakers knew that smokeless powders were likely to be used.

My guess is that when a firing-pin is ejected and the hammer or the square shank of the tumbler fails, it is the latter two that fail first. Any antique is likely to have been dry-fired a lot, but you should stop it unless spring-loaded snap-caps are used, and examine the hammers very carefully for cracks. Soaking them in gasoline and seeing if any weeps from cracks after it is dried should be a help. If I had to replace a hammer, e.g. with the castings available from https://www.peterdyson.co.uk/ ,I would look for heavier ones than the originals



Another gun worth looking for, for this purpose, would be the Greener GP shotgun, which is basically a Martini action, wider and with the larger threads required for the 12ga cartridge. It is a lot stronger than most shotgun actions, and isn't materially weakened by an excellent takedown system. But the few in the US are unlikely to be as cheap as they often are in the UK, and heaven knows what difficulty you might have with a personal import nowadays.

[Rcmaveric]

I hoping the CVA Hunter or Scout becomes the poor mans T/C Contender. Hopefully someone start making custom barrel chambering's so I can start filling my laundry list of calibers.

[Toolmaker TN]

Ok, found one of them at least.
Article was a five part series "A Modest Schuetzen" by Steve Durren. He used an H&R Handi as the basis for the conversion.
Have all five in the series. Will keep looking for the Johnson article.
If you'd like a copy, PM me your email and I'd be happy to scan and send it to you.

[Texas by God]

50-70 and .577 Snider blackpowder rounds are good candidates for a project like this. I wouldn't use an old Hopkins & Allen or such but a H&R Topper or Savage 94 are well up to it.

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[Nines&Twos]

Something else to be considered besides the softer steels of shotgun receivers is the firing pin. Shotgun often have larger firing pins that protrude more than rifles. You can find yourself in a position where you get pierced primers. Also, if the fit of the firing pin to the firing pin channel is loose and pressures get high enough, the primer can extrude into that and cause headaches.

[Gewehr-Guy]

There have been lots of Swedish rollers imported in the country, some of them rebarrelled to more popular cartridges. Maybe you could find one of the old 12.7x44 barrels and turn it down to fit in a 12 gauge and solder or epoxy it in. They are basically equivalent to a 50-70, which uses a black powder load smaller than a 3-1/4 dram , 1-1/8oz BP shotshell load, so it seems like a safe conversion to me. Just an idea I've toyed with, but maybe you're looking for something a bit bigger. A .577 Snider would be interesting too, but a suitable donor barrel might be hard to find cheap.

[RPRNY]

50-70 and .577 Snider blackpowder rounds are good candidates for a project like this. I wouldn't use an old Hopkins & Allen or such but a H&R Topper or Savage 94 are well up to it.

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Good advice. The H&R SB2 receiver was designed for 65,000 psi. There are quite a few 444 Marlin barrels out there that could be bored out and rechambered for an obsolete black powder cartridge and would be rock solid. But 22" doesn't do the BP cartridge any favors. The H&R Buffalo Classic in 45-70 would be a good donor but they are going for silly money these days. I had, and moved on, a 20ga deluxe barrel for an H&R, which was a 12ga ribbed 28" barrel blank that was only bored to 20 ga. It was errr, rather heavy. While it wasn't a good shotgun barrel, it would be a great candidate for a liner. Anyway, a 20 ga Topper barrel, lined and mated to an SB2 rifle receiver would be one route. But rather than a full liner, the more common route with an H&R would be a barrel and stub. Buy a full SB2 rifle and then fit the desired new barrel and chambering to the stub of the original barrel. If you pop over to the H&R Forum on Greybeard Outdoors, the H&R experts (dangerous enablers one and all) can explain it all really well and fill your head full of many visions.

[justashooter]

years ago i got a Remington Rider single shotgun that has rifle sights and a Belgian made barrel insert in 38-55, it shoots just fine in either 12 guage or 38-55. these inserts were about $12 in 1905, when the shotgun was $17. the period ladder sight was an add-on. still have that gun in a nice leather case.

[Ballistics in Scotland]

50-70 and .577 Snider blackpowder rounds are good candidates for a project like this. I wouldn't use an old Hopkins & Allen or such but a H&R Topper or Savage 94 are well up to it.

They would both be just about perfect for the job when you've got them. But good .50 barrel liners are available from TJ's or Track of the Wolf, and .577 would probably mean grafting in a new barrel.

I've never really liked the idea of a stubbed barrel, although I am sure it is practical enough. I believe I would make the joint further forward, perhaps with a shallow step or disguised with a band for a rear sight, sling swivel or stock screw.

[Jedman]

I have built 9 or 10 50-70 barrels for H&R's and CVA Apex's. I have 2 that are nearly ready to sell except for the finish. The Apex barrel is SS and is done finished and the H&R I have not yet parkerized as that is the only good permanent finish I can do.
If interested send me a PM.

Jedman

[Ballistics in Scotland]

Good advice. The H&R SB2 receiver was designed for 65,000 psi. There are quite a few 444 Marlin barrels out there that could be bored out and rechambered for an obsolete black powder cartridge and would be rock solid. But 22" doesn't do the BP cartridge any favors. The H&R Buffalo Classic in 45-70 would be a good donor but they are going for silly money these days. I had, and moved on, a 20ga deluxe barrel for an H&R, which was a 12ga ribbed 28" barrel blank that was only bored to 20 ga. It was errr, rather heavy. While it wasn't a good shotgun barrel, it would be a great candidate for a liner. Anyway, a 20 ga Topper barrel, lined and mated to an SB2 rifle receiver would be one route. But rather than a full liner, the more common route with an H&R would be a barrel and stub. Buy a full SB2 rifle and then fit the desired new barrel and chambering to the stub of the original barrel. If you pop over to the H&R Forum on Greybeard Outdoors, the H&R experts (dangerous enablers one and all) can explain it all really well and fill your head full of many visions.

It sounds like any receiver made for a centrefire bulleted round should be good for a rifle, but although I am quoting from distant memory now, that may not be entirely the case. I believe the .44 Magnum rifles and maybe some others, or some of them, were built on shotgun receivers and yet marked SB2 on the barrel, which was to that specification. I would think that those receivers are quite a bit better than some earlier cast iron ones used to be. If they investment cast one in alloy steel, why not investment cast the other - and good mild or lower-spec alloy steel is then just as easy to use as cast iron. But I would want to find out more before using one.