Hi,

So I bought the Win low-wall in 25-20 SS and am anonymous AR friend is helping me get the components I need (I can only get Bertram brass here -need I say more?). What is the correct bullet diameter for the SS? Can both be used? Do you guys shoot cast bullets? What weights? Blackpowder?

Lots of questions...

The 25-20 single single shot is probably limited to the domain of Schuetzen and cast bullet shooters.

I shoot the .25-20 Win in the shorter repeater version.

here's some data on the lyman gas checked bullet in the 25-20 singl shot
68 Lyman 257420GC IMR IMR-4227 8.5 1,430
68 Lyman 257420GC IMR IMR-4227 9.0 1,546
68 Lyman 257420GC Alliant RL-7 10.0 1,300
Remarks: 1 to 1 1/2 inches
68 Lyman 257420GC Hodgdon H-110 8.0 1,350
Remarks: 1 1/2 inches
68 Lyman 257420GC Hodgdon H-110 9.0 1,498
68 Lyman 257420GC Alliant 2400 8.0 1,600
Remarks: maximum/1 1/4 inches
68 Lyman 257420GC IMR IMR-4198 9.0 1,350
68 Lyman 257420GC IMR IMR-4198 9.5 1,425
Remarks: 1 1/4 inches
68 Lyman 257420GC Winchester W-680 9.0 1,200
68 Lyman 257420GC IMR SR-4759 8.0 1,350
Remarks: 1 1/2 inches
68 Lyman 257420GC IMR SR-4759 9.0 1,700
90 Lyman 257464GC Alliant 2400 8.0 1,650
90 Lyman 257464GC IMR IMR-4227 8.0 1,300
Remarks: 1 1/2 inches
90 Lyman 257464GC IMR IMR-4227 8.5 1,385
90 Lyman 257464GC IMR IMR-4227 9.0 1,450
Remarks: 3 1/2 inches
90 Lyman 257464GC Alliant RL-7 10.0 1,290
Remarks: 1 1/2 inches
90 Lyman 257464GC Alliant RL-7 11.0 1,500
Remarks: 1 1/2 inches
90 Lyman 257464GC IMR SR-4759 7.0 1,238
90 Lyman 257464GC IMR SR-4759 8.0 1,450
90 Lyman 257464GC IMR IMR-4198 10.0 1,440
90 Lyman 257464GC IMR IMR-4198 10.5 1,550
91.5 Lyman 257312GC Alliant 2400 7.0 1,375
91.5 Lyman 257312GC Alliant 2400 8.0 1,675
Remarks: 3 inches
91.5 Lyman 257312GC IMR IMR-4227 8.0 1,300
Remarks: 3 1/2 inches
91.5 Lyman 257312GC IMR IMR-4227 8.5 1,425
91.5 Lyman 257312GC IMR IMR-4227 9.0 1,450
Remarks: maximum
91.5 Lyman 257312GC Alliant RL-7 10.0 1,300
Remarks: 2 inches
91.5 Lyman 257312GC Alliant RL-7 11.0 1,460
Remarks: 2 inches
91.5 Lyman 257312GC IMR SR-4759 7.0 1,150
91.5 Lyman 257312GC IMR SR-4759 8.0 1,350
91.5 Lyman 257312GC IMR SR-4759 10.0 1,700
Remarks: appears OK
91.5 Lyman 257312GC IMR IMR-4198 10.0 1,425
Remarks: 1 inch
91.5 Lyman 257312GC IMR IMR-4198 10.5 1,500
Remarks: 1 inch
91.5 Lyman 257312GC IMR IMR-4198 11.0 1,575

I own a Winchester Model 43 Bolt Action in .25-20 Win. It a great rifle and my loads consist of: 7.0 grains/SR-4759/86 grain SP. Another good load is: 10.0 Grains/IMR-4198/86 grain sp. I've taken several Squirrels, Woodchucks, and even a Coyote.

Hello cewe. You will have to "slug" the bore to determine the correct bullet diameter. It should be in the .257-.261 inches range. The Winchester should shoot cast bullets of 65 to perhaps 90 grains weight very well. Black powder could be used but careful cleaning procedures should be used to prevent corrosion of gun and cases. Vapodog's data is very good and shows lyman bullet mold numbers. You will need a smokeless lube with smokeless powder and blackpowder lube for the black. Check out the black powder cartridge forum for generally useful information on such reloading.