The Shooters Box Conversion Inserts in Stock

[Geoff B]

Wait, rifled?! Is That reaaaaallllly legal? Since there is 37mm to 12Ga Adaptor.

Please don't go there!

[Beeron]

If I want to shoot 9mm or .45ACP out of a 12 guage would I first need the 12 to 20 adapter and then insert the 20 to pistol adapter? Or does it not work like that?

Depends,
Apart from the direct 12 - whatever calibre of which there are many, Some of them say they are compatible with larger reducers and some say they aren't.
So for versatility, you could get a 12 - 20, and then 20 - 410, and then 410 - whatever pistol calibre you wanted.
That way if you own a 410 or a 20ga, the sleeves will work in those as well.
That's how I have been doing it; however, option for 410 - pistol cal's are limited so its not a perfect system yet.

I have a bunch of these in various calibres including a set that I bought which goes from 12-20 and then to 410.
I also have a 12-22 that is at least as accurate as I can be with the bead on my modified Cooey 84.

Just picked up a 22WMR to add to the kit.

Also, before I completed my modified Cooey project, I used the 3" one sin my 870. They work fine. Just a bit of a pain in the loading and unloading.

[KND]

https://store.prophetriver.com/the-s...tgun-adapters/

Need more 12 gauges adapter to 45 acp or 9mm.

[Suther]

Wait, rifled?! Is That reaaaaallllly legal? Since there is 37mm to 12Ga Adaptor.

Yes. There is no legal limit on rifle barrel length, only handguns have a minimum barrel length.

From sec84 of the Criminal Code, (b) is the relevant part:

prohibited device means

(a) any component or part of a weapon, or any accessory for use with a weapon, that is prescribed to be a prohibited device,

(b) a handgun barrel that is equal to or less than 105 mm in length, but does not include any such handgun barrel that is prescribed, where the handgun barrel is for use in international sporting competitions governed by the rules of the International Shooting Union,

(c) a device or contrivance designed or intended to muffle or stop the sound or report of a firearm,

(d) a cartridge magazine that is prescribed to be a prohibited device, or

(e) a replica firearm; (dispositif prohibé)