Re: Which 338???Who to build it?.
I believe the 338's are extreme range calibers. They really offer little advantage over 7's and 30's until we approach the mile mark. At this point, the 300's seem to hit cruise control, and seemingly carry forever.
Aside from the the already mentioned reasons, the Norma is a favorite because it is capable of superb extreme range accuracy. Several factors contribute. The first is efficient, consistent powder burn. Single digit Extreme Spreads are achievable and common. A look at case capacity vs velocity quickly illustrates some cartridges simply don't burn powder effectively. When you have a 15% increase in powder and a 4% increase in velocity you have to ask, where is all the extra powder going? Most likely, down the bore, unburned, eroding the throat, and wreaking havoc with your velocity. The Norma cartridge is also ready to go, no forming required, and the brass is excellent.
The overbore cartridges are much more difficult to achieve tight velocity spreads. Fire forming, necking down etc introduces more challenges to pinpoint accuracy and tight velocity spreads. The Norma delivers pinpoint extreme range precision with ease.
The bigger cartridges are fun. They have more wow factor, more cool, and more velocity. Do they sacrifice pinpoint extreme range precision for a little more velocity? Some of them do. What good is an extreme range round if it scatters bullets everywhere but on target?
This is my thinking. I've shot many of the 338's. I've done load work for a few. I freely admit my experience with the 338's is somewhat limited and these opinions are carried over from much experience with smaller calibers. Of course, as a gunsmith, my job is to build what interests you, what gets you excited. I build 'em all, enjoy 'em all!