Thread: Ordered a 45ACP/12ga rifled insert

a couple of these on the market , thought I would try one of the rifled ones by chiappa. They are an insert into the shotguns chamber allowing it to fire a variety of pistol ammo. The chiappas have about 8" of rifling. Anyone tried one of these? My bet is accuracy will not be overly high, the tolerances would need to be loose enough to get it in and out of the shotguns chamber.

Sounds like they be a bit of fun , where did you order them from and what calibers they come in ?

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Hi Im In australia, so just our chiappa distributor. Whoever brings your chiappa x-calibre guns in, should have a handle on these. I think there are 8 calibres covered, you can buy separately or as a kit. Us prices https://www.chiappafirearms.com/category.php?id=23

Mimms2 it does sound in relation only to gas operated actions. We have similar here I think, the legislation relates to conversion kits for handguns/semi-autos etc to fire 22LR. Might be worth any Kiwis interested checking it out with the cops or your gunstores. You might be okay.

nope a sub calibre conversion like this is NO WHERE NEAR semi auto fire...its a slow single shot at best...you still have to manually remove and replace rounds....these chamber inserts are nothing at all like a semi conversion kit....chalk and chainbar lube.

Be a cool idea to use the rest of the 12ga hole as a suppressor if you could ensure insert and baffle alignment

Subcal inserts can be very accurate depending on the type - especially the German kinds that lock into the chamber with a free floated barrel and are indexable/adjustable. The kind I'm familiar with are ~12 inch barrel, maybe 8 inch.

Helped prove to me that accurate shooting is far more dependent on accurate sights and stable shooting platform (IE a full stock) than overall barrel length, as a pistol length insert in a 12 gauge will very easily shoots similarly to a rifle in the same caliber, while the equivalent barrel length in a pistol is a challenge. It's all intuitive really, but made me far more willing to trust short barrel rifles.

One thing you could try with the chiappa inserts is a brass sleeve that matches the chamber dimensions. Would need to take care not to dent or burr it, but would give a good snug fit. Could also use a piece of sustarin or the like.

Originally Posted by canross

Subcal inserts can be very accurate depending on the type - especially the German kinds that lock into the chamber with a free floated barrel and are indexable/adjustable. The kind I'm familiar with are ~12 inch barrel, maybe 8 inch.

Helped prove to me that accurate shooting is far more dependent on accurate sights and stable shooting platform (IE a full stock) than overall barrel length, as a pistol length insert in a 12 gauge will very easily shoots similarly to a rifle in the same caliber, while the equivalent barrel length in a pistol is a challenge. It's all intuitive really, but made me far more willing to trust short barrel rifles.

One thing you could try with the chiappa inserts is a brass sleeve that matches the chamber dimensions. Would need to take care not to dent or burr it, but would give a good snug fit. Could also use a piece of sustarin or the like.

Those inserts you can buy often centre by means of O-rings. Turning down a barrel to be epoxied inside a brass 12G cartridge would seem to be the way to protect the SG chamber - and cut away a section of the rim to avoid the insert getting ejected every time you open the shotgun, and will also ensure the barrel is indexed consistently. I like the idea of using the spare SG barrel ahead of an insert to dampen sound, at least a bit.

Only question is, would the receiver handle the more focal pressure of a rifle cartridge? The total pressure may be similar.

Originally Posted by Cordite

Those inserts you can buy often centre by means of O-rings. Turning down a barrel to be epoxied inside a brass 12G cartridge would seem to be the way to protect the SG chamber - and cut away a section of the rim to avoid the insert getting ejected every time you open the shotgun, and will also ensure the barrel is indexed consistently. I like the idea of using the spare SG barrel ahead of an insert to dampen sound, at least a bit.

Only question is, would the receiver handle the more focal pressure of a rifle cartridge? The total pressure may be similar.

Brass shotgun cartridge, now that's using your head and keeping it simple!

Don't know if I've seen many inserts in anything more than pistol calibers? I was thinking of a rifle length firearm in equivalent cartridge (IE 9mm, .22, 38 spl, etc) when saying that they shoot similarly. I could see a rifle cartridge insert in smaller cartridges (30-30, 223, 300 blk etc) being a useful tool on a handi rifle with SB2 frame that's built for regular rifle cartridges. Don't know if there would be any issues around the 12 gauge barrel itself, but seeing as they're all the same geometry to fit into the frame there're less complications than with a standard shotgun. Next issue would be insert barrel length... start getting into bigger cartridges and most of the powder won't be burnt by the time the bullet leaves the short insert barrel.

Originally Posted by canross

Brass shotgun cartridge, now that's using your head and keeping it simple!

Don't know if I've seen many inserts in anything more than pistol calibers? I was thinking of a rifle length firearm in equivalent cartridge (IE 9mm, .22, 38 spl, etc) when saying that they shoot similarly. I could see a rifle cartridge insert in smaller cartridges (30-30, 223, 300 blk etc) being a useful tool on a handi rifle with SB2 frame that's built for regular rifle cartridges. Don't know if there would be any issues around the 12 gauge barrel itself, but seeing as they're all the same geometry to fit into the frame there're less complications than with a standard shotgun. Next issue would be insert barrel length... start getting into bigger cartridges and most of the powder won't be burnt by the time the bullet leaves the short insert barrel.

I can see someone coming up with a choke insert with a disc at the muzzle end drilled for the appropriate diameter, plus a bit extra for tolerance. Crap suppressor no doubt, but a flash hider, yes.

Other option would be a screw on device for the rifle insert muzzle, that extends forwards just short of the muzzle of the shotgun. Would get around the issue of forgetting the end cap is on when switching to birdshot. Something like this (the middle portion, the insert minus sleeve, from an aliexpress solvent trap - just narrower to fit into a SG barrel:

Originally Posted by Cordite

I can see someone coming up with a choke insert with a disc at the muzzle end drilled for the appropriate diameter, plus a bit extra for tolerance. Crap suppressor no doubt, but a flash hider, yes.

Other option would be a screw on device for the rifle insert muzzle, that extends forwards just short of the muzzle of the shotgun. Would get around the issue of forgetting the end cap is on when switching to birdshot. Something like this (the middle portion, the insert minus sleeve, from an aliexpress solvent trap - just narrower to fit into a SG barrel:

Attachment 123394

What about a barrel insert with a built in suppressor on the end of it?

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Interesting ideas fellas. One question is, would the 12ga barrel by itself offer any sound reduction? I dont mean to supressed levels, but say compared to a 7" pistol barrel . Would the the 20-28" shotgun barrel at least muffle the noise a bit? or would it make it louder, like a trumpet effect?

Originally Posted by sixtus

Interesting ideas fellas. One question is, would the 12ga barrel by itself offer any sound reduction? I dont mean to supressed levels, but say compared to a 7" pistol barrel . Would the the 20-28" shotgun barrel at least muffle the noise a bit? or would it make it louder, like a trumpet effect?

It would probably ever so slightly quieten the sound, but probably not a ton... not anywhere near an actual suppressor. Slightly different beast, but bloop tubes for target rifles are similar to shotgun overbarrels on an insert rifle barrel and are permitted in the USA, they get pretty anal over anything that could be considered a suppressor due to sound reduction.

I like cordite's idea on the monocore baffle.

Originally Posted by sixtus

Interesting ideas fellas. One question is, would the 12ga barrel by itself offer any sound reduction? I dont mean to supressed levels, but say compared to a 7" pistol barrel . Would the the 20-28" shotgun barrel at least muffle the noise a bit? or would it make it louder, like a trumpet effect?

Originally Posted by canross

It would probably ever so slightly quieten the sound, but probably not a ton... not anywhere near an actual suppressor. Slightly different beast, but bloop tubes for target rifles are similar to shotgun overbarrels on an insert rifle barrel and are permitted in the USA, they get pretty anal over anything that could be considered a suppressor due to sound reduction.

I like cordite's idea on the monocore baffle.

Thanks canross. Sixtus, forward venting muzzle brakes in directing all gases forward (think L.E. Jungle carbine rocket nozzle!) significantly increase felt recoil but at the same time HALVE the noise experienced by the shooter. It will increase the noise perceived forward of the gun. Has to be why they put that device on, they knew muzzle brakes in those days, but it would just make firing that nasty short thing really unpleasant in the days before hearing protection for men. At a distance the noise will be the same from any direction. A forward-open SG barrel with rifle insert would do the same.

putting it muzzle forward would be asking even harder for baffle strike
unless you cut it down and done a muzzle forward on like a 4 inch barrel

a series of washers that are 12 ga on the outside (18mm) and 45 cal (12mm 11mm+ 1mm clearance) on the inside that are pressed in with 18mm pipe cut into one inch pieces for spacers would be the simplest

just gotta make sure that it all lines up