Opening up the chamber on a 12/14 gauge Greener Mark III

[sjb323]

I recently picked up a 12/14 gauge Greener Mark III police shotgun. It's a pretty unique old Martini Henry action shotgun, with one major problem -- 12/14 gauge ammo is almost impossible to find! For those who don't know, the 12/14 gauge is a 12 gauge shell that has been necked down to 14 gauge. The idea was to create a proprietary round that was only available to occupying police forces. This was basically an early form of gun control in the event that a civilian came into possession of the shotgun. Anyways... when imported into the US, some of these shotguns had the chambers (and maybe the bore?) reamed out to accept standard 12 gauge loads. Unfortunately, there is very little info on this process floating around on the interweb. I know that it's a stretch, but has anyone here done this, or have any info that they are willing to share on how to go about accomplishing this? Any help is appreciated!

[Fjold]

It could probably be done on a lathe easier than any other way unless you had a gun drill. You're talking about opening the entire length of the barrel from .693" to .729". I wouldn't want to try that with a hone, you could be there for months. I guess you could broach it, but the tooling costs would be prohibitive.

[john323]

Check with Bob Day at R and D barrels.

johnsgunsmithing@live.com
Monterey Park Ca
323-722-3903