Re: 338 Edge VS. 338 Remington Ultra Mag.
I'm not sure why a good gunsmith wouldn't chamber a Remington 700 in a .338 Lapua. Remington's M24A3 is a .338 Lapua and it's basically a Rem 700 action.
I personally would go with a .338 Edge as the .338 RUM Brass is getting hard to find and the overall cost of brass for the .338 Lapua is much more expensive than the RUM series. I do however like the qualities of the .338 lapua with the shorter case and being able to seat the bullets out farther but I'd rather have the case capacity of the .338 EDGE.
After I get done with this current build I'm working on, it's on to the bigger calibers. I don't have a .338 caliber anything so I'm looking seriously at the Edge. It would make a good long range hammer for me. This will be next years project.