Well boys, as few of you know, I have a soft spot in my heart for Soviet Block Cartridges. I know, a terrible thing for one to admit. At least I'm not a cold war vet.
The one that seems to have become my all time fave is the notorious "7.62x25 hand howitzer catridge." A couple of the surplus loads have been chrony'd at 1700 fps with a 85-90g boolit. Pretty good for a auto cartridge.
Now for some time I've had a nice commercial Martini Henry .303 of Belgium origin. The rifle is a bit beat up, but mechanically sound. These have been converted to quite a few different calibers. And are one of the stronger actions available for custom falling block rifles.
Now I have tossed around the idea of chambering this rifle with a new barrel to the 7.62x25 cartridge for use with cast boolits at about 15-1600 fps. However, I think the conversion is gonna be somewhat difficult considering this is a rimless cartridge. So, I've been doing some thinking about a solution. Use an existing rimmed cartridge with a body diameter of close to the same size and resize it in the 7.62x25 sizer die to neck it down. I'd have a 7.62x25r essentially.
Boy does this boggle me. At first I though of the .357 or .38spl case. Might work. Case diameter on the 7.62 is 0.387" while the .357 and .38 have a 0.379" diameter. However I'm fairly concerned about that 0.01". Think the cases will rupture?
A standard reamer could be used for the barrel since all I'm doing is essentially what was done with the .45 Rim cartridge. But this difference in case size is making me wonder.
What do you all think?