Ran across a rifle and set of RCBS dies the other day in 308 Norma Improved. Can pick up for $350.00 so probably will even if it ends up a rebarrel project. Anyone know anything about this round? Don't know if it just has a 35 or 40 degree shoulder or if it's been blown out on the shoulder as well. Any thoughts?

No mention of it in Ackley's Vol I or II. Nothing on it in Donnelly's Cartridge Conversions either. You could always do a chamber or sizing die cast and find out.

Probably you could ream it to .300WM..

Since it has dies, fire form a few cases and shoot on...

Forgot to ask, what rifle ?

It's a FN Mauser in pristine condition. Thinking that the improved version might offer the same case capacity of the 300 WM but case will still be short enough that bullets won't be seated as deep as the Winnie. I already have a 300 WM and a 30-338 so need this like another hole in my head but hey, wives always seem to need more shoes too.

For $ 350 including the dies I wouldn't pass it up.

There is no way one can do anything in the way of "improving" the 308 Norma and get anything close to 300 Win mag capacity. Case taper is already pretty minimal and a change in shoulder angle might increase capacity by a couple of grains. Blow the shoulder ahead, so you have a short neck like the 300 Win Mag., and you will still have less capacity.
The 308 Norma, as is, might be the very best designed 30 magnum ever. Case length fits standard actions, the neck length is adequate, and capacity is just right for common powders. In my opinion, any changes only serve to screw it up. GD

I had a Kleinguenther in 308 Norma. I shouldn’t have sold it. It was a fine shooter.

There you go. The 308 Norma is already better than the short necked pos wm.