NEED HELP ON BSA MARTINI

[CHRIS MARTIN]

I want to convert my 22 long rifle BSA Martini (model 12) to 22 Hornet. The chamber reaming is pretty obvious, but how to I go about converting the firing pin from rim fire to center fire???? Thanks for any help.

[gunboat]

Don't forget to use .221/222 bullets --

[gunboat]

The model 12 or "rook rifle" is the commercial equivalent of the "310 cadet" rifle -- the cadet firing pin should solve your problem -- the cadet extractor may also work or you could open the 22rf extractor up -- these are excellent actions and make fine small bore rifles --but the 22rf will likely have a slightly smaller bore -- my ha-penny

[CHRIS MARTIN]

Thanks. The blueprint drawings for the BSA show a bore of .223, the size of the original 22 Hornet bullet. Modern Hornets are loaded with .224 bullets, so I may have to handload with .223 bullets (still available) once we see how it shoots. I have an offset firing pin on order, we'll see if that addresses the rimfire to centerfire conversion problem. Please keep any comments coming in !!!!!

[gunboat]

Off set firing pin ? The bore must be offset from center then -- I have not messed with a .22rf #12 so that is a bit of surprise -- I have seen 340 mausers with the offset bore, makes bolt modification un-necessary -- Yes, the .223 are still available -- I still have a box of Sisk .223 45gr. --Looking forward to hearing "how she shoots" ---

[CHRIS MARTIN]

Well, it's not clear semantically if the rifle's bore is off center/offset; its just that the firing pin's "bore" (or tunnel) through the breechblock "aims" at the rim rather than at the center of the cartridge's end. The offset firing pin keeps the same firing pin tunnel but places the pin portion of the firing pin itself off center (the firing pin is a 1.5 inch tube about 3/16 inch in diameter and the firing pin itself is a "nipple" on the end perhaps 1/4 inch long). Thus, with a new firing pin exit hole (bored lower in the breechblock), the offset pin will come out lower on the breechface and thus "aim" in the center of the cartridge. What interests me now is whether or not the old firing pin hole will need to be plugged up...and, I can't see why it would have to be. Don't really want to weld it up and ruin the bolt's heat treatment. Will have to think on that. Of course, the other option to to fool around with the shape and fit of the breechbolt and associated mechanism and thus drop the bolt about 1/8 inch in the receiver...but I think that would be tricky. Thanks for the various input; please keep it coming!

[gunboat]

It may be easier to use a "310" breech block -- I seem to recall the 310 firing pin and spring being about 7/16 diameter -- Is there enough meat to rebore your block -- Lowering/raising the block will disturb the perpendicularity of the breech face to cartridge -- The under lever tongue could be modified to change block location -- This is not a BSA #12 Target model I hope --