Re: Going to build a .338 and have some questions.
I think it is a pretty safe opinion that the 338 Norma/ Lapua can be done on a 700 action, if you go with an aftermarket bolt like PT&G. Having said that, I would look at spending alittle more and go with a custom action to be on the safe side. The EDGE is a great caliber, have owned one and was in the process of building another until some health issues came up. As we all know the EDGE does 2830-2850 w/300SMK and a 30" barrel.
It can easily be done in a 12.5-13.5 rifle with Nightforce scope. But if a 30" barrel is going to be a problem you should seriously concider the 338 Norma.
I had one built this past August by SSG, but sold it recently. Dumb move. It will get you 2730-2750 with the 300gr SMK with Retumbo out of a 26" barrel. It also does not require an extended magbox, as the COAL w/300SMK at the neck/ shoulder junction is 3.55-3.60. Might even have enough magbox length to use the 338 Berger's when they come out.
What I would do is run the #'s and see what will work best for you and what barrel length is acceptable.
One thing I will say is that the 338 Norma brass is unbelievable. I have 15 reloads on my 30cal version with this brass, and have only thrown away 3 pcs due to slightly loose primer pockets.
Personally, I would either go with the 338 EDGE and a 30" barrel, or a 338 Norma with a 26" barrel.
I don't see any advantage the Lapua brings to the table over the 338 Norma.
In my experience, the 338 brass quality of the Norma is as good if not better than the Lapua.