would this work? This has to be a common thing.

So, I have a barrel cutoff in 35 cal from shortening a rifle. perfect "pistol length barrel"

Couldn't I chuck it in the lathe and cut the external profile to fit into the 20 ga chamber of my handi rifle slug gun? Or maybe my 12ga smoothbore? Then chamber it in 357 max. or even just 38 special, doesn't matter much. Add a couple o-ring grooves for "self centering" and snap on a couple Viton O-rings as a friction fit.

It would end up being like one of those shotgun chamber converters, just 2-3 times longer, since the muzzle would be resting in the actual barrel, not just a 3" or 3.5" insert.

No reason I can't do this and end up with a safe product, is there?

yes you can make identical to a shotgun shell and it will work. As a 38/357 pressure you should be ok But that 357 max is a totally differant animal, I personally would not go that route.

With good barrel steel in the insert there should be plenty of metal to hold magnum pistol pressures in the 12 gauge chamber with a .357 diameter chamber. My .357 max doesn't get loaded to 60,000 psi anyway. No advantage. I like the idea of using a rifle length insert myself with scope base drilled and tapped. Should be a dandy one gun does it all survival gun. I'm looking at a .327 version too.

No reason you couldn't make it work and be safe. I would check with the ATF to see if firing a pistol cartridge in a shotgun would classify it as an NFA weapon before proceeding. I remember reading something about that awhile ago, but could be wrong. Have fun, but do some research so you don't open yourself up to harassment.

sorry I did not make clear my issue and it is the receiver. The 357 max has alot of back thrust in a small diameter but heck what do I know go for it if you want!

next dumb question then, I was doing some measuring. Turns out the back of the barrel cutoff is less than .1" larger (but still larger!) than a 20ga rim. Perfect! ....too perfect.

Anyways, that begs me to use my handi ultra slug hunter in 20ga since that has a scope on it already rather than the 12g which just has the bead. For those who have used the inserts, can I assume that the boolit in a 38 (let's be honest, there's no point in 357 mag, it should be 38 or a max! :)) never touches the shotgun barrel on the way out? or are there cases when it can and does bounce off the barrel on the way out?

I ask cause it's not mission critical for my 12ga, but I'd hate to be scraping against the rifling of my slug gun....

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Originally Posted by nekshot

sorry I did not make clear my issue and it is the receiver. The 357 max has alot of back thrust in a small diameter but heck what do I know go for it if you want!

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That gives me more confidence too. I have done the 357 max on an SB1 and shot 250 grain hornady bullets to 1800-1900 fps in a 16" barrel handi. (not more than one box mind you, but it worked fine!)

I've read an article in the 60's that described just this sort of insert for shotguns. In that case the author made an insert for the .44 magnum.
He went into calculations on the amount of thrust on the breech face and by his reckoning firing the .44 Magnum in a common 12 ga single barrel would be safe.
I'm not convinced that all shotguns would be safe to use with such a powerful cartridge. I've seen too many older shotguns with caved in breech faces to assume that all are that strong. I have one here now with the receiver split down the middle, it was given to me to strip for parts, the barrel is still good. A shotgun action like the old HR Topper or similar shotguns that were often fitted with .30-30 rifle barrels should be plenty strong enough.

Not looking to get mired in the safety aspect. Let's just say I'll ream to 38 special. better for me anyways, and I can still shoot heavy cast boolits, just with trailboss.

Want to focus on the possibility that the boolit will ever contact the shotgun barrel. Does that never happen, or is it possible, does it happen?

If you use electrical tape or groove the muzzle end of barrel for o ring that is snug at the determined spot it will center itself. The only way you would touch the outside barrel would be one whale of a phart load and at that slow speed it wouldn't damage anything. I find the forcing cone to be interesting on a shot gun barrel. I wish there was a easy way to get rid of them, as that would allow the insert to be on a nice taper.

Yes, I have no idea how to deal with the forcing cone, so I planned to just avoid it completely. Turn my cutoff to the final barrel diameter (probaby .600-ish or slightly less depending on the rifling diameter) for the entire cutoff till about 1.5" from the end. Then go sloppy chamber diameter till where the "brass" would be on a shotshell then get more serious about tolerance.

Maybe cut a ring or two of delrin so the barrel steel doesn't contact the chamber or rifling. I have a bunch of viton o-rings, they should last OK at the service temp of a barrel.

How long is this piece of cutoff barrel? I realize that chamber inserts let you shoot pistol cartridges out of shotguns but what I've seen doesn't have any sort of rifled barrel, relying on the shotgun barrel. If you use less than 16" of cutoff barrel, would the ATF have something to say about it?

the cutoff is something like 6 inches. already far longer than most 38 revolver barrels.

Pretty sure the ATF won't have a cow since the insert will technically have a slip on linear compensator that is way over 18 inches long.

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Originally Posted by petroid

How long is this piece of cutoff barrel? I realize that chamber inserts let you shoot pistol cartridges out of shotguns but what I've seen doesn't have any sort of rifled barrel, relying on the shotgun barrel. If you use less than 16" of cutoff barrel, would the ATF have something to say about it?

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It is the barrel length of the shotgun that matters. Put it in one and they just see it as an 18"+ rifle. Just don't have a 12 gauge flare gun around if you have a 12 gauge adapter.

Are items like these available with rifled barrels? I wonder how accurate it would be. If there is enough play to insert and remove it easily, would there be a major poi shift each time it is removed/reinserted? Or would it fit tight enough against the receiver to align properly.

Check MC Ace co. Out of Alaska. They make chamber/barrel inserts.

I use a .22 rim fire insert in a .45-70 Sharps. It is a very precise/accuarte device. Made by Crosnos (sp?)

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Originally Posted by Whiterabbit

Yes, I have no idea how to deal with the forcing cone, so I planned to just avoid it completely. Turn my cutoff to the final barrel diameter (probaby .600-ish or slightly less depending on the rifling diameter) for the entire cutoff till about 1.5" from the end. Then go sloppy chamber diameter till where the "brass" would be on a shotshell then get more serious about tolerance.

Maybe cut a ring or two of delrin so the barrel steel doesn't contact the chamber or rifling. I have a bunch of viton o-rings, they should last OK at the service temp of a barrel.

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I thought to have the insert touch the barrel - lapped fit in smallest part of choke, and a no touch fit from there until the absolute rear of the insert in the chamber (slight relief .005" in rest of chamber and barrel).

Keep in mind I don't know what I'm talking about here I'm just repeating what an old gunsmith friend said not long before he passed away.
I was at his shop one day and he had built a rifle on a Russian single barrel shotgun. I asked him if this could be done with any shotgun. His fear was the large firing pin and accompanying hole wouldent stand up to high pressure stuff. The Russian Gun had a small firing pin with a pretty tight hole.
I don't recall the caliber he had it chambered in.

38 special would probaly be fine.
how are you going to extract/ eject

Some years ago I bought a remington rider single barrel shotgun that had rifle sights, and a belgian made 38-55 full length liner that had a complimentary extractor that interacted with the shotgun extractor, sliding on 2 pins. It is reasonably accurate. Since then I have made many inserts in 45-70, 30-30, etc. I have a few german made 16 gauge doubles that have greener crosspin design and insert sets, making them "double rifles" that retain their shotgun function when liners are removed. Getting them correctly regulated is the fun part.

Most vintage shotguns do not have a breach that will tolerate serious backthrust, so small base diameter cartridges that develop more than 1500 foot pounds energy are a bad idea. Most vintage shotguns also use a large diameter firing pin that is not closey fitted to the firing pin hole, so "ringed" primers is a possibility. Professional modifications of shotgun to rifle usually involve adding an insert sleve to the breach face.