I have an extra Martini International collecting dust. I have my eye on it for a winter project. I could just re-barrel it to a .17 Mach 2 However--Here is my question?
Could I screw on a .17HMR barrel? Is there enough lever throw to extract the extra lengh of the HMR? The present barrel,receiver, and action have been proofed with BNP Birmingham Nitro Proofed to 8 tons per square inch. That would be the English long tons. Do you see any troubles here? Anyone know a BSA Martini expert here in the States?

Another option you might want to consider would be to sleeve the existing barrel to 17 cal and chamber for the 17HMR or the 17Mach2. 8 long tons (2200lbs) psi would be 17,600 psi. Off the top of my head I don't know the pressure figures for either round, but that would not be hard to find.

Craigster,
Are you meaning sleeving like they do in a shotgun or installing a liner? I suspect the latter. Redmond makes a 17 liner just for that purpose.

BTW, the only Martini expert that I know is Bob Snapp in Michigan. High end custom martinis. He has "retired" but works on projects he likes.

i have converted one to 22 mag without any problem by putting a liner in the original barrel and cutting a new chamber. plenty of throw on the lever to extract the case. i have also installed a liner in one and chambered it to the mach 2. so i believe it is entirely possible to make on into a 17 hmr without much work if on is set up with the tooling

Yes, I meant to say liner. Brain fart. BTW, a local smith down here did one in 17M2 for a friend of mine on an old beat up Winchester 52, seems to work quite well.

Max:
You are the guy I've been looking for. If the lever had plenty of throw for the 22 mag it will be the same for the HMR. How have your Martinis shot after the liner jobs compared to the original .22? Which was better the Mach 2 or the HMR? Are you still shooting irons? Who did the work? If you are using a scope is it interferring with that wonderful/fun forward extraction?

many of the imported bsa's that came in through navy arms several years ago were lined sometime in their past. i sold a bunch of them and about half of them were lined. they all shot well. the couple that i have lined all shot real good as long as you get the right liner for the purpose. it didn't seem to make much of a difference if the liner was glued in or soldered in.the mach2 i did shot good and i let a friend talk me out of it and he is working on restocking it. i put scopes on them and use high or medium rings with the smaller scopes. it isn't to much of a hassle to load with it but i would be lying if i told you they don't interfere.