converting shotguns to rifle calibers


April 6, 2004, 12:15 AM
Okay, I've seen a .410 frame converted to a double 8X57, IIRC.

Many single barrel shotguns have rifle barrels up to .30-30 caliber readily available.

At the top end, Krieghoff and Merkel will retrofit their double 12s to .470 NE, but do require the receiver back for proof testing. Which implies that the receiver as built can take the load.

Just how big/powerful a cartridge can the standard shotgun receiver take? I would assume as long as the pivot bar is solid and the locking mechanism, that the straight back recoil on a cartridge head shouldn't be a problem.

Anyone with experience or breech pressure numbers to toss out?


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Dave McCracken
April 6, 2004, 05:23 AM
Winchester made a couple Model 21s in 405 Winchester and 45-70, no special tempering, etc.

The Brits made double rifles in calibers like 375 H&H and 470 Nitro Express on what looks like traditional SxS actions. The hard part is getting both barrels shooting to the same point. This is called "Regulating" the barrels. It takes handwork, experience and patience. IOW,it's costly.

Valmet used to market O/U combo guns, with barrels in 12 gauge and 308, 30-06, etc. The lower barrel could be tweaked to shot to the same place as the upper by adjustable hangers. Not cheap, might still be available from Sako on special order.

Is this going to be in a book?

April 6, 2004, 05:47 AM
The thing with most double rifles is the working pressures. Amost all of them have a top locking bar to keep them closed during firing of the guns. Shotshells deal with relativaly low woking pressures with fast burning powders. Rifles tend to use very slow powders with high pressures developed down the lenght of their bore. This causes an awful lot of stress on the receiver. That's why most double rifles are quite heavy because of the reinforcement required in their receivers.

For a while someone was building barrels to interchange with Ruger Red Labels in rifle calibers, but I believe one of the largest available was .45-70 which is a relative soft shooter with low pressure.

It is also entirely feasable to build inserts to drop in the bores of shotguns like Kolar and Briley make for some of the smaller cartridges, although 'regulation' or point of impact of the barrels would be almost impossible.

April 6, 2004, 10:41 AM
On the EAA questions page ( they talk about a 45-70 insert for their 20" barrels. They are being made in Italy and we hope to have them in the USA by the end of March 2000. The inserts will fit a 20" Baikal side by side shotgun that has factory installed screw chokes. Retail price for a barrel kit (One kit includes - one 45-70 barrel, two point of impact adjustment bushings, one locking nut, one rear sight and rear sight screw ) $ convert both barrels you must buy two conversion kits.

April 6, 2004, 12:50 PM
A guy here in Colorado wrote a book about how to make a double rifle from a shotgun. He favored relatively low pressure rounds like the old N.E. calibers, a favorite being .450 3 1/4", IIRC. He had several of his guns at a show here. Pretty nice.


April 6, 2004, 01:23 PM
Shotguns may use lower pressures but the area that it is applied against on the recoil face of the reciever is positively HUGE compared to rifle calibers. Someone with more time could do the calculations based on total surface area of each, I'm betting that even magnum calibers in the 60K psi range are not significantly higher, IF they are even higher, than a 12 guage load at 13K psi.

I would guess that regulation of the barrels and the extremely limited market driving costs way up is why we don't see more double rifles made from shotguns.

April 6, 2004, 02:57 PM
Not for a book. It's a "I've got machine tools and heat treating gear. If I ever have the time and one of these old receivers, what could I do?" type of questions.

I saw the .405 Winchester conversion, and it looks like muzzle energies around 3-4K ft lbs in rifle are easily supportable on a 12 gauge receiver. Possibly on a 20.

I would guess it's that non-safari shooters don't generally think of double rifles. Pity. Cheaper double rifles would be excellent for hunting American game, and they point so nicely. Say a double .300 magnum? 7mm magnum? .338?

If the lock on a H&R can handle a .308, I don't see why it can't handle something above.

btw: Speaking of books, some frothing Michael Moore fan reviewed "Freehold" and called me a "right winger" even though I'm not. (I'm not sure he knows what a right winger IS.) In response, my sales rank jumped 4K points back up into the top 10,000. And this is on the second printing.

There was no contact info, so I'm spreading the word online various places. Insult me and call me names and boost my sales. Thanks, y'all!:neener:

Dave McCracken
April 6, 2004, 05:17 PM
Thanks for the chuckle. $%^&* Moore...

"No such thing as bad publicity"-Larry Flynt.

April 6, 2004, 05:47 PM

Here is a link to a US made SXS double rifle site. I would dearly love to have any of them, but my financial staus will not permit it.

April 7, 2004, 09:26 AM
My guy down in Clearwater,FL, built a set of 45-70 barrels that fit into a Stoeger 20" "Stagecoach" shotty. Did a nice job with it.

MM - Please drop me a heads-up when "Weapon" and "Hero" come out so I can order a signed copy like I did for "Freehold". Thanks. Turns out a guy here at the Embassy corresponds with Ringo, small world.

April 8, 2004, 01:48 PM
Mad mike,

PROMISE you won't wreck those damascus barrels to do this?

is putting good rifle barrels on that receiver what you want to do?



Jim Watson
April 8, 2004, 04:40 PM
Butch Searcy built his first double rifles on Browning BSS receivers before starting to make them from scratch.
Dietrich Apel would put rifle barrels on Ruger Red Labels in .45-70 or 9.3x74 R.
There was a gunsmith whose name I don't recall who would send a Winchester 101 action to a contact in Germany to have rifle caliber barrels made, then he would finish out the complete gun.
Browning sold combo sets on Superposed action 20 ga and .30-06 or .270.
Valmet had rifle barrels in 9.3 and .308 available for their Remington 32 type O/Us.

I think those last two point out the (lack of) difference between a low pressure acting against the large area of a shotshell head and a high pressure acting against the smaller area of a rifle casehead.

But British double rifles just LOOK like double shotgun actions. They are considerably stronger. My friend's .450 BPE is a big stout gun and that just for black powder pressure.

EAA is advertising a double rifle in various calibers from .223 to .270 (higher pressure than .30-06) with user adjustable regulation. Wouldn't the 7.62x39 be fun? And a handy .30-30 equivalent hunting rifle with safari style.

April 11, 2004, 02:06 PM
The EAA conversion kits-
I have been looking at one of their SXS's and was wondering if the conversion units are somewhat permanent or can you change them out fairly quickly/easily? Would love to have a double gun in 45/70 :cool: .

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