I am going through the same delema as well. I have been reading everything I can find, and it really appears that there is no clear winner. The gunsmiths that I talked to all seem to say that no matter which cartridge you pick (338rum, 338 Edge, or 338 Lapua) you will most likely have a gun that shoots 2850fps with a 300 grainer. With my build specs the Lapua will cost about $450 more than an edge build (including dies cost and brass, and both on custom actions).
I really wanted to have 2950-3000fps, and go with the Lapua Improved versions. But it seems that most gunsmiths I talk to say the gain is actually marginal (like 50fps). With the additional cost of custom dies, and having to fireform, I just don't think it is really worth it. It seems like Kirby's version, 338 Allen Xpress, may have the largest case volume of the improved ones I have looked at. It is also nice to know you can buy fireformed brass and dies from him (not sure of the costs). It sounds like 3000fps is possible with this version, but I am fearful that the acuracy loads will be about 2900fps.
One of the bord members I personally know had Joe Starnes build and edge for him, and I think if he could do it again he would do the Lapua.
I guess I am leaning towards the standard Lapua beacuse of the brass quality, and I think there may be a little more potential accuracy because of it. I am also going to try a 30" tube with 1-10 twist to help keep the velocity up, and get full use out of the powder burn.
I know this subject gets beat to death sometimes, but I can't wait to read what the others have to say.
