Friday, September 28, 2007

.50 Alaskan Brass for Conversion to .45-75 Winchester

The .50 Alaskan brass arrived from Starline yesterday. I'm chuffed. Great stuff. Although I had Mom here for dinner last night, I grabbed a couple of minutes to trim and run one of the cases through the .45-75 full-length sizing die. Good to go. The one empty case ran slick as snot through the action.

Here's some dimensional info.
.348 Win.50 Alaskan.50-90 Sharps
Rim Diameter.603".6015".651"
Rim Thickness.0665".067".064"
Case Head Dia.546".545".5585"

This surprised me because I saw and was told that dimensions for the .50 Sharps and AK were the same. I'll have to load the cases to get dimensions on neck diameters as requested. The .50 AK case sized in one go and with the smaller case head they are noticeably easier to size than the .50-90 Sharps. Both cases will go in one go.

As to sizing, the shoulders in my chamber seem to be forward of those in the sizing die. This could result in working the brass excessively. I'm thinking that the rifle manufacturers used the original chamber dimensions from original rifles and the die makers used the cartridge dimensions as published by Winchester and, as with many BP cartridges of the time, there's some slop to allow for reliable functioning despite fouling. I will probably partial full-length size these cases. If you look at the 2nd and 3rd case from the left in the below photo you can see just what we are talking about here... (click on the photo to go to a larger version) The fired cases have a different shoulder configuration.

It is a trick to find the right pre-fireforming trim length when sizing this case up from .348 Win or down from one of the big .50s. Some good news is that .50-95 shooters will only need to trim the .50 Alaskan case to length, size and load.

No comments: