2) Minimum gain
The 6.5-06 A Square shoulder is 0.442. The 6.5-06 Ackley shoulder is 0.455".
The difference is 0.013". That is like $3 thick.
Your inherent prejudice is obvious.
While you demean the AI version because of shoulder diameter alone, it is not the only variable which makes a difference in performance. The improved shoulder diameter plus the increased shoulder angle both contribute to increasing the case capacity.
It's unfortunate though, that far too many only consider the Ackley versions to be necessary for increasing velocity by increasing the capacity. The reality is that there are some cartridges which benefit from the improvement for other reasons.
The sharper shoulder of Ackley-style cases creates a better, systematic burning of powder, often allowing us to use a broader selection of powders which can enhance the overall performance of the cartridge even though the velocity gains may not be as spectacular as desired. This can be the primary impetus for the improvement.
3) Obcurity
a) The 6.5-06 Ackley is so obscure it is not in the Quickload 3.9 library.
b) The regular 6.5-06 is obscure enough. I had to pay triple to get Lee Precision to make a custom collet neck die mandrel from Lee Custom Mandrel reduction service for 270 mandrel from a collet neck die down to 0.262", but leave the top 1/4" alone to fit a 270 collar
c) I had to pay double to get a custom FL sizer body from Forster neck honing service to hone out fee from 25-06 body to 0.292" neck.
To label a cartridge as 'obscure' simply because H.G. Broemel forgets to include it in a cartridge library is ludicrous. There are dozens of cartridges which he
does include which are more antiquated and obscure than the 6.5-06 AI by many measures. Then there are the other cartridges which have been skipped for one reason or another, let alone the 100 plus mistakes I've noted in the most current version. I have passed these on to his company on two separate occasions and have yet to see or read anything regarding any changes.
The 6.5-06 wildcat is so popular that many reloading manuals list recipes for it. At least two blown-out versions — meaning the walls are straightened and shoulder is pushed forward — are fairly popular. The 6.5 Gibbs reportedly reaches 3,325 fps with a 120-grain bullet, and the 6.5-06 Ackley Improved hits 3,100 fps.
Ron Spomer
https://www.buckmasters.com/Magazines/GunHunter/Articles/ID/2646
/The-30-06-Cartridge-Family
I feel bad that you aren't realizing any economy given your direction chosen for obtaining dies. For those who are willing to choose a different direction, Redding has standard FL dies sets in 6.5-06 AI available for purchase. If you want a finer control over neck sizing, you can order 25-06 bushing dies and simply switch the bushing to the ones suitable for your neck tension. There are other variations available as well.
Best of luck with your project.
