.25-06 Ackley Improved
The standard .25-06 compared with the .25-06 Ackley Improved, which treads close on the heels of the .257 Weatherby Magnum (right)

How to work out handloads for the .25-06 Ackley Improved

Q: I have had my .25-06 re-chambered to .25-06 Ackley Improved. I intend to use this rifle primarily for deer hunting with 115 to 120gn bullets, but am having difficulty finding any loading data for this cartridge other than in Ackley’s Handbook, which is 60 years old and uses powders which are no longer available.

Is there any other source of data for this wildcat? If not, can you suggest some starting loads?

John Waters

A: When a standard .25-06 is fire-formed to the Ackley version, two principal changes that take place are a steepening of the shoulder angle to 40 degrees and a .48mm (.019”) expansion of the case body to a diameter of 11.7mm (.460”) at the point of the shoulder. 

This results in about a 7.5gn increase in water capacity of the case, or around 11.5%. 

Based on the larger internal capacity, it is possible to increase powder charges by about 5-6%, which would translate to about a 2.5 to 3gn increase with slow powders such as AR2209 and AR2213sc behind bullets of identical weight.

Therefore, a separate table of loads for the .25-06 Ackley isn’t needed. You can simply use load tables for the standard .25-06 Remington. 

Start 3gn below maximum and increase charges one grain at a time until the standard cartridge maximum is reached. Further load increases should be kept to ½gn increments, keeping in mind that 2.5-3gn ceiling. 

Somewhere in that span of plus or minus 3gn, you will probably find the best load for your individual rifle.




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Nick Harvey

The late Nick Harvey (1931-2024) was one of the world's most experienced and knowledgeable gun writers, a true legend of the business. He wrote about firearms and hunting for about 70 years, published many books and uncounted articles, and travelled the world to hunt and shoot. His reloading manuals are highly sought after, and his knowledge of the subject was unmatched. He was Sporting Shooter's Technical Editor for almost 50 years. His work lives on here as part of his legacy to us all.