Have you ever heard the saying "make do or do without"? Well that was my choices to be able to shoot a used 25Bullberry Contender barrel that I recently bought at a gun show. I was not able to locate used dies for this caliber and the Redding dies listed on Midway USA are $230.00. I decided I would have to try and come up with a way to form and load for this barrel or selling the barrel without shooting it. The first thing I did was locate a drawing of the 25Bullberry and the Load Data web page https://loaddata.com/Cartridge/25-Bullberry/1155 had the drawing, then I downloaded the SAAMI drawing for the 30-30. Everything between the 2 drawings were really close except for the neck diameter. Here are the minor differences:
-25BB shoulder is +.015 further forward
-25BB Shoulder is +.052 longer than 30-30
-25BB neck is -.056 shorter than 30-30
All other SAAMI Specs are identical
What all that meant to me was minor tweaks of the dies I chose to use is all that was needed to be able to form the 25BB brass easy with just neck sizing. I started out with a 257 Weatherby sizing die that was cut down on the lathe. That didn't size the neck enough and some bullets were loose when loading. I looked at other drawings and the 250Savage looked like it may work so today I picked up a set of used RCBS 250 Savage die that looked to be never used. I formed 2 cases and the necks diameter came out exactly what the 25BB drawing showed at .2785. Loaded a cast bollit over 8.0gr Unique and fire formed the 2 cases. The resulting neck diameter was .287 and the shoulder was formed very nice. I've been talking with user "jsizemore" about this chambering and he sent me an article about the 25BB and 3 of his fired case. His fired case chamber in my barrel just fine and his fired neck size measures .282, a slightly tighter chamber than mine. So here is what I have settle on forming and loading for the 25Bullberry round in a contender.
I start by full length sizing the 30-30 case (before I did this I crushed a few cases). Next I form the neck using the 250 dies until the case will chamber and locks in the closed position in the barrel. Next I load a fire forming round and fire the case which Irons out and forms the shoulder. I will continue neck sizing and loading until the case get hard to close in the action, at that time I can remove the decapping/expander stem from the 30-30 sizing die and full length size the brass again. A note here I screw the die in to touch the shell holder then back off a half turn so not to push the shoulder back. I've already tried this and it works.
Here is a picture of what the case work looks like.
left to right 30-30, neck formed to 25BB, fire formed brass.