I've had a little Martini action Cadet rifle for years, but never shot it much because stamped on the barrel is "32-20". Now, we all know that the 32-20 bullet is far too small for the Cadet bore, so I just put it aside for future study. A shame too, because the bore is gorgeous.
While rummaging through my pile of stuff I found three boxes of Kynoch .310 ammunition, so I compared one of them to a 32-20 and discovered that:
The 32-20 case is longer than the .310.
The 32-20 is a mild bottleneck, compared to the straight taper of the .310.
The 32-20 case is smaller in diameter at the mouth by quite a bit.
Bullet diameters are, of course, different.
Now, here's my question. This little rifle was no doubt one of the imports back in the early 1960's, but wasn't sporterized or changed other than the barrel marking. I've seen countless articles stating that a 32-20 reamer was run into the chamber in order to make them more "saleable" here in the U.S. So ASSUMING this is true, how in the world did they get the reamer in there? Remove the barrel? Doesn't look like it at all, yet the 32-20 AND the .310 will both chamber. If indeed they reamed it, it would only lengthen the chamber somewhat but not change the contour. In other words, the .310 bullet might have to travel a bit to reach the rifling, but it will shoot. For that matter, I could shoot 32-20 in order to fireform the case and reload with the correct bullet, assuming the case didn't split (that's an awful big expansion for that little case!).
If the above is true, I can still load and shoot the .310 Cadet cartridge with some hope of accuracy. All I would need is a mold for the correct diameter heeled bullet which is available from Australia I believe.