300 RUM brass in 338 edge

[martyj]

I have both types of brass and the shoulder on the 338 edge brass appears to be different.
My question is when you neck the 300 rum brass to 338 do you use a full load to form the shoulder on it or a lighter load.

 

[SnkBit]

Shoot full loads. The 338 Edge is not a fire formed case. You're just seeing a difference in brass manufacturers.