25-20 Winchester Single Shot

[Iron Jim Rackham]

Does anyone know the maximum pressure of the obsolete 25-20 Winchester Single Shot cartridge? I've got an 1891 Winchester Low Wall that I'd like to rechamber as a 30-30. The pressure of a 30-30 with 160 grain bullet is around 33,000 CPU. I could load it softer, but am curious what the type of pressure the 25-20 Single Shot generated

[Zeb Gray, #36839]

25-20 SS & 25-20 WCF have similar characteristics though different cartridges.  You can probably use 25-20 WCF pressure data.  

 

I too, have a Low Wall In 25-20 SS.  1892 mfg. with a single set trigger.  Fun shooting.  

[Cusz M. Dutch SASS Life 55326]

I am sure a full case of Goex might work...

[John Boy]

28.000 CUP …. https://en.m.wikipedia.org/wiki/.25-20_Winchester  

[High Spade Mikey Wilson]

The original black powder 25-20 WCF rounds were about 20,000 PSI. The later smokeless powder rounds averaged about 28,000 CUP.

[Tom Bullweed]

Opening a low wall barrel to a .30-30 would be mighty thin chamber walls.  That old steel was likely surface hardened, so those new surfaces might not be as strong.

If it was my gun, I would consider a .32/20 barrel.  

[Iron Jim Rackham]

Thanks for the feedback. I knew the pressure of the shorter 25-20 WCF was north of 27,000 CPU but was curious if anyone knew the pressure generated by the longer and more powerful 25-20 pushing an 86 grain bullet.  The barrel is very thick and the case diameter of the 25-20 SS measures .296 as compared to .401 for the 30-30 but there is plenty of steel remaining after re-boring.  A 30-30 generates  23,000 CPU pushing a 160 grain lead bullet at 1,562 fps, and 33,000 CPU pushing a jacketed 160 grain bullet at 1,900 feet per second. 

 

Has anyone "updated" the obsolete 25-20 SS to another caliber?

[Michigan Slim]

Look up Reboring by JES. He does great work and could guide you where you need to go.