Originally Posted by Texasyankee
RANDOM QUESTION: If the 7mm Ackley Improved Magnum can be fire-formed from 7mm Remington Magnum brass, how is it that a 7mm Rem has a capacity of around 83 grains, while the 7mm AI Mag seems to have a capacity of only 80 grains?
Welcome to the forum.
If you read through the first page of this thread, post #17 in particular, you will see the 7 mm Ackley Magnum (AM) existed before the 7 mm Remington Magnum, and was originally formed from .300 H&H brass. Unlike the Ackley Improved (AI) series of chamberings, it did not have a parent cartridge you could just fireform to the larger AI size.