I am not connected to this item in any way. I suspect - I hope - someone can take advantage of what appears to be an opportunity to "build your own double rifle" without ruining a set of shotgun barrels. Barrels have 3-groove Enfield rifling, whatever that is.

In the white double rifle blanks

Looks like a good start but who knows what they are being fit up for...
Also looks like a dovetail lump so that can be changed out pretty easily as long as the bore centers work with your action and even if they don't, these barrels could be taken apart completely and reworked to bring them a bit closer together and to change the top extension I would think. The rim diameter will dictate that and looking at the breech end, they may be as close together as is practical once the rim recesses are cut.
I have heard of three groove rifling in some precision match rifles and the like these days but not sure of its use in big bore doubles.
There was a 303 Enfield with 3 groove too but mot many just after WW2 IIRC.

Well, if only it were that simple, we'd all do it.

So first the centres of the bores must be in exact alignment with the firing pin holes in the breech of the parent shot gun action.

That's the key.

Next comes the alteration needed to the existing forend iron and its woodwork and the question of the loop. And new extractors or ejectors will need to be made.

It'd be a lot of work this project. And for what? A weapon that will in fact be less lethal, for practical purposes, at the realistic ranges at which it will be used, that a simple side by side shot firing and old fashioned Forster or modern Brenneke slug.

.577 Snider was never a 'big game' calibre for good reason and so the project is daft. OTOH you might get very lucky and get a match with an action...it's a lottery this project...but you might just win...

quote:

.577 Snider was never a 'big game' calibre for good reason and so the project is daft...

I think the seller was using the Snider round as an example - a rather poor example. The barrels are not chambered.

The rate of twist is apparently super slow. I wonder what they were originally cut for?

I wonder, then, if it is some sort of "bore" rifle? Not a .577" per se, not a 20 bore, but perhaps a 24 bore? For ball or "collar stud" bullet? Or maybe a "Colindian" bullet?

Or it sounded like a good idea at the time.

If a .45-70 double using factory Hornady ammo with a planned accurate range of 100 yards will work for you, you might consider the slide in tubes.
The MCA .45-70 adapter insert for my turkey gun will plunk them into a 8inch bull all day.

And here is another approach from another forum:
http://www.doublegunshop.com/f...er=426250#Post426250

The seller says that they have a really slow twist, (approximately 1/2 turn over the length of the barrel). Wouldn't that be a black powder round ball twist?

I'm having a spare shotgun barrel set for a Valmet 412 made into a set of DR barrels in 459/400. I should have them soon.