I picked up a nice "US Government" marked Enfield a couple weeks back and wanted to get the best possible dies for reloading. Peter at Hirsch had a Forster Ultra Benchrest seater, so I picked that up. I like bushing dies, and wanted the Redding micrometer seater for neck-only sizing my cases. Turns out Redding doesn't make one for .303 British, only regular type-S dies. So, I thought about it for a second and two things came to mind:
1) In all other neck sizing dies, the body of the case doesn't touches the die until the neck has already been completely re-sized (if it ever does at all). Hornady Neck sizing dies are generic. They are drilled and don't contour any particular cartridge.
2) The .303 British cartridge dimensions are smaller than .308 Win. in all areas except for the neck. So, backing off the .308 die so that it doesn't touch the shoulder on the .303 case amounts to the same thing as Hornady's die. And with a bushing die, I can control the neck tension precisely.
So, I tried it with my 308 Win. FL bushing die and it worked like a charm. However, my Redding 308 Win. Competition Micrometer Neck sizer worked even better. The sleeve supports the .303 case nicely. I'm getting neck runouts under 0.001".
1) In all other neck sizing dies, the body of the case doesn't touches the die until the neck has already been completely re-sized (if it ever does at all). Hornady Neck sizing dies are generic. They are drilled and don't contour any particular cartridge.
2) The .303 British cartridge dimensions are smaller than .308 Win. in all areas except for the neck. So, backing off the .308 die so that it doesn't touch the shoulder on the .303 case amounts to the same thing as Hornady's die. And with a bushing die, I can control the neck tension precisely.
So, I tried it with my 308 Win. FL bushing die and it worked like a charm. However, my Redding 308 Win. Competition Micrometer Neck sizer worked even better. The sleeve supports the .303 case nicely. I'm getting neck runouts under 0.001".
