I recently purchased what was supposed to be a Stevens Model 12-Marksman- 44 shot -rifle re-barreled in 38 special. Sounded cool I thought, and the price was right. I am not looking for a super flat shooting single shot, just a plinker to add to my collection of other odd ball firearms. Well it turns out that this was re-barreled to .375 not 357-358. Someone did a really nice job of fitting what appears to me as a modern .375 barrel. it is no longer slip fit to the barrel extension it seems to be  attached to it. The chamber is for a 38/357 and the bore is slugged at.375. 

I am planning to Breech Seat 130 grain 38/55 cast bullets over say 4 grains of Bullseye which is a standard low pressure target load for .38 specials and figure it should be plenty safe. I can not think of any reason why that load breech seated should really have much more pressure than it would have pushing a bullet of the same weight that is .020 larger in diameter. If someone out there has a edjumaked opinion as to a better starting load or a reason not try it please let me know. If anyone has heard of this combination of bore and chamber please let me know, and finally if anyone has an idea for a name for this caliber please let me know.

Thanks
Allen

When I slugged my Remington roller in 38 XL, it came out .364-.3645 land to groove (odd number of lands, so land to land not possible).  Have an original 30 L.I.L inside lubed hollow base Ideal tool/mold, so no problem shooting it with 357 Max cases,  rare no. 8 tool.  Caliber in question may be 38 Long Ballard.  Have one with a rotten bore, so sleeved it in 38 Special, fun shooter.
James

Hey  Txbrill !!!

I too bought a Marksman about (Twenty-five year's ago) with the same reason you have here (it's still in the coffee can) !!!  Unlike the other small Stevens, it has a solid frame/firing pin for any extra back pressure needed so I think you have a safe load to enjoy !!!  BTW, check out the developed pressure of a .22 Lr...  You will be surprised !!!   

Ed...