does anyone have the case measurements for this cartridge. My step dad has a pre-64 mod 70 that was chambered somewhere in oregon back in the mid 50's. its a long magnum cases with conventional shoulders.

any help would be great

Red,

What does the headstamp of the cartridge have embossed on it.

I have checked all of the references that I have, including a P.O. Ackley loading manual from the early 60s, but there is no mention of a 300 Ackley Magnum.

Good Hunting !

Red Rhino,
Your safest bet would be to cast the chamber and measure the cast. Cerrosafe is avaialble though Brownells for the casting.
In the event that it is the .300 Ackley Magnum, it was made from .300 H&H shortened to 2.600" and fireformed in the chamber.

Bill

The length of the case is 2.8, imagine a 300 weatherby with conventioal shoulders

In Parker O. Ackley's book "Handbook for Shooters and Reloaders" he refers to the 300 Improved Magnum (Ackley) It has the forty degree shoulder and he states to use 300 Weatherby loading data for it.

In view of that you should have a great rifle. Hope you have the dies. Brase will be easy to form.

Good Hunting
Steve

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