expanding necks of 300 WSM

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haffordite2

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I have a quantity of 300 WSM that I would like to expand the necks to use in a 325 WSM . Dimentionally the cases are identical except for the necks. Any compelling reasons not to do it? Any difficulties to watch for?
Thanks
 
I neck up 6mm to 308 regularly with just a touch of imperial sizing wax on the case body and a swab inside the neck with a Q-tip, your brass will shrink in length a fair bit, but just trim them all uniform, over time as you fire them they will stretch back out to the trim to length. If short brass is going to cause you OCD issues then load the cases up with 12 grains of unique and cream of wheat, cap with a piece of cardboard and next time your out at the range fire away, your necks will expand and the cases will be closer to the original length that you started with.
 
I did a few by accident last time I was sizing a large batch of 325WSM brass. Didn't notice a couple 300s in the mix. They went through the dies no problem, and you can't tell (except for the headstamp) that they weren't originally 325WSMs. There was a noticeable increase in force required to get the expander through the neck, but only enough that I knew something was different.

On previously fired brass, make sure you clean/polish the inside of the neck, and lube the expander. Makes it go way smoother.
 
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