I have a new 25-06AI coming tomorrow. I have several opinions on best way to get the brass. #1- fire form old reloads already FL sized for the 25-06 and seat bullets out into lands #2- Buy new 270 brass ,trim to 2.510" and then size w/ 25-06AI just till bolt closes then fireform #3- use new 25-06 brass,seat bullet into lands and reduce charge 37grs of 4895 and heavy buttet(117gr or 120gr) and fireform.. I'm confused>> as to best method.. since I have a lot of reloads already loaded easiest for me would be pull bullets and seat them longer into lands and fireform.. (pressure may be too much)//// Advise please/.. thanks Doc Stone Ps-- got a new deluxe set (3 die) of reddings (25-06AI) on the way..

I find #2 the most satisfactory. I'm not sure about the LOA that you quote, but whatever is proper for your chamber is the right measurement. Most .25-06's (and IMP's) use a nominal 2.495" like the .30-06. .30-06 brass is not too large in the neck to start with and will usually squeeze down to .257 nicely, particularly when starting with unfired brass. Depending on how generous your chamber's neck diameter is, the larger .30-06 brass may give you a better fit in that department, providing a bit more material for neck turning.

Brass formed as you describe in #2 usually provides accurate loads on the first firing, allowing you to begin load work-up from the get-go. Using undersized brass which "headspaces" on the bullet jammed into the rifling will work, but the performance of the load in the initial firing is meaningless for load development purposes.

If you have lots of ammo loaded now, just go ahead and shoot it as you would normally until it is used up. If the chamber is cut properly, your accuracy should be fine and the cases will form close enough to be able to work up loads once all the cases are formed. As long as the neck/shoulder junction hasn't been set back, your cases will chamber close enough to fireform to as close to finish dimensions as you can hope for, even with setting the bullets out. This way you'll at least have properly headstamped brass. Besides, 25-06 brass is reasonably cheap so experiment with it a bit if you're not happy with the first loads.
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