I built a 416 Barret 5 years ago when they were the next big thing. Bartlien barrel. LAR action, The works. I used all hunting bullets and settled on Rocky Mountain Bullets. Bottom line there are better cartridges, If you want a wildcat then a 338 snipe tac, 338\408, the Allen Mags. especially the 375 cheytac, snipe tac or allen mag ( all pretty much the same) will out perform the 416 Barret and you will have a better bullet selection to choose from.
I might add the aforementioned Rocky Mountain Bullets BC is advertised extremely high. I have serious doubts if these bullets were judged on the same BC scale that Barnes, Berger and other premium manufacturers are judged by.
If a person is looking for a non wildcat for ease and availability of components it is Very hard to beat the 338-378 Weatherby. Fuel it with a 280gr Barnes LRX and RL25 (around 109.5gr) and a Win Mag primer loaded to a 3.85 coal you will have a serious non wildcat long range contender. EASIER than a specialty EDGE, A Square, Excaliber, etc.