Re: 25/06 Ackley Info
In 1987 I purchased a Sako Sporter (L61R Action) in 25/06 calibre, which I tested and chronographed various loads, used in the field (Australia) as a hunting rifle on medium game such as feral goats, pigs, kangaroos, emus, and with also some use on rabbits, and foxes.
After some 400 shots, I had it rechambered using the existing barrel, to the 25/06 Ackley Improved with 40 degree shoulder.
I found that capacity of the standard 25/06 case increased from 65.8 grains (new brass), and 68.0 grains (fired) to 72.2 grains after fireforming in the Ackley chamber.
Using the 100 grain Nosler Ballistic Tip, I found that velocity increased from 3320 fps using 56.0 grains IMR 4831 to 3,550 fps (in the Ackley) using 60 grains IMR 4831.
Using the 120 grain Nosler SPBT, I found that velocity increased from about 3,100 fps using 56.0 grains IMR 7828, to 3320 fps (in the Ackley) using 60.0 grains IMR 7828.
I have been using the 100 grain ballistic tip, and its performance on medium game has been terrific.
I have now fired some 1600 shots in the rifle, and the throat has eroded about .250 inches, and while I would normally rebarrel a rifle at this stage, it is still shooting well, so I have decided to continue to use it for a while.
Recently, I had a custom 25/06 (Sako L61R action, shilen SS barrel) returned to by the South Australian Police, after it was stolen from me back in 1983. I handed it to my gunsmith about 1 month ago for rechambering to the Ackley improved, so I will soon have 2 rifles in this calibre.
Just a word of warning, I have noticed that there is a wide variation in reloading data for the same bullet weights in this calibre, so there is obviously a considerable difference in chamber dimensions and subsequent case capacity, so as always when working up loads be conservative.
I have found that when working up to maximum pressure using fireformed cases, if you start with what would be a near maximum - maximum load in a standard 25/06 case, you will be pretty safe.
If you want my chronograph load data, just email me and I will send it to you.