Does anyone know if 300 Savage brass can be formed from 243/7-08/308 casings? I greatly appreciate any advice from those that have used these or any other casings.

The 300Sav and the 308Win are almost identical right up to the shoulder. The shoulder angle and neck length are the main difference.
You should be able to just run the 308Win brass thru a 300Sav die, and trim to length.

.300 Savage could theoretically be formed from any of these three, but the .308 should work much better since you won't have to expand any necks. .308 brass is usually cheaper and more plentiful than the others, anyway.

Some people will tell you that you'll have to ream the necks of brass formed from .308, but since most chambers are somewhat oversized, it is likely that unreamed necks will actually come closer to fitting your .300 chamber. I would only thin the necks if necessary for concentricity.

308 brass is the only brass I use anymore for my 300 savage in my contender.

The standard 300 savage sizing die will work fine, but trim the 308 brass down prior to sizing and then recheck the length.

I tried sizing before trimming and with the dies I have, I was not able to fully full length size the brass.

Also, my chamber is of very close tolerance and when I need to full length size, I use a small base sizer. Sometimes using the standard die, I would have to force the round in to the chamber and with the SB sizer, there is a normal chambering.

It's cheaper brass and IMO, the only way to go with the 300 savage, unless you go with the rimmed version using the 307 brass and go through the same sizing and trimming operation.

Have fun & good luck,

HBL

I recently made a bunch from millsurp .308. Its damn near the same case. It works great but you need to reduce loads just a bit because of the extra thickness of the brass.

Mil-surp .308 brass will be cheaper, but Russell Sports in Calgary lists new Remington brass.
http://www.russellsports.com/files/f81-100.pdf

Bye
Jack