I'm kinda like Roy. A little bashful and shy about recommending a good smith.
But........if I was talking to a good friend and he wanted to know of the best damn long range gunsmith around......I'd recommend Kirby Allen of Allen Precision Shooting. I'd also tell him he goes by "Fiftydriver" on here, that is if he was interested.
I'd also tell my friend that Kirby built a full custom for me and one for my hunting buddy and my next one will be built by Kirby also, that is if my friend was interested.
Then I'd tell him to see below and check it out.
YouTube - 7mm Allen Magnum, water jug and gun/bullet info