I need some help figuring this out and some suggestions on how to fix the problem.

I just pulled the barrel from a Martini model 12 and found that the barrel shoulder has only been touching on 1/3 of it. This tells me that something isn't square, either the action face or the action threads.

Now a bolt action is easy to setup to recut threads square with the bolt, but with the Martini.....what do you line it up with?? and how do you check which is not true??

Ian Owen

Ian, IIWY I'd first make a thread mandrel, that is a threaded fixture ~1"-2" long with a CENTERED bore and a perpendicular shoulder to bear upon the receiver face. You can then fab a large-headed brass lap to stick through the central mandrel hole and indicate the non-perpendicularity of the breechblock face via machinist's layout blue or similar. For the Cadets I use a short section of barrel that originally had a ring in the chamber & so had to be cut back & rechambered, I just use a cartridge case as an indicator.

The receiver face perpendicularity can be indicated by abutting the mandrel's shoulder against it.

You may well find that none of the 3 agree with one another, or you may find that 2 of them do indeed agree. Whatever the case, you now have more info for making a decision as to the easiest path.

I personally have found that in most cases it's best to alter the breech face and receiver face to agree with the threads, since most single shot receivers are difficult to hold for rethreading. A lot depends upon the exact angle of the breechblock's rise as opposed to the angle of the threads and the relative clearances. Your Cadet is relatively easy to align, or at least I've found them to be easy.

Please be advised that many Cadet breechblocks retain considerable case-hardening and will probably require 'measures' to alter the dimension of the skin. Good luck!
Regards, Joe

Hello Joe, Thanks for the reply, this is the only Martini I've pulled to bits that has been this far out.....but I have only used BSA 22lr actions in model 12 and 12/15. I haven't pulled any cadet actions to bits for any of my projects.
Regards, Ian

Ian, in the US we usually refer to all the small Martinis as Cadets, meaning merely a smaller version of a larger example, whether RF or CF. Sorry for the nomenclature confusion.
Regards, Joe

Joe, Thanks for that explanation, the 310 cadets still fetch good money here, but I can pick up a model 12 or 12/15 in 22lr for around $200-$250 and they are still plentiful and make nice light quick handling rifles.

Looking at the front of this action the barrel face has been touching the action face from about 10.30 to 3 with the rest showing absolutely no signs of metal against metal contact and in fact slight signs of rust.

Studying the action the barrel tenon threads should be parallel to the inside sides of the action and square with the inside rear face of the trigger group/breachblock cut out.

If ths is the case then all I need to do is come up with a way of holding it in the lathe to square the threads to these surfaces.

Lucky I'm not trying to make a living doing this.
Regards, Ian