I've been scrounging around for 300 Savage brass. I shoot 300 Savage in my Rem. 760 pump rifle. I love shooting this rifle and it is a great one, but ammunition is getting hard to come by and 300 Savage brass is expensive when I can find it. I recently bought a Savage M11 in 308 Win and was doing some research on the cartridge and loads when I ran across this.
"The .300 Savage distinguished itself further by serving as the parent to the .308 Winchester (7.62x51mm NATO) cartridge, a round that was developed for the U.S. armed forces in the 1950s and which is still in use today."
In looking at the case dimensions closer, they are almost an identical match save the shoulder position and angle, and case neck length. The 300 Savage is a bit shorter than the 308 Win so making 300 Savage cartridges from a 308 Win cartridge should be a doable thing. I think some experimenting is in order. I will likely have to inside neck ream the resulting cartridge, but that is okay if it results in usable 300 Savage cartridges.