Krieger, Hart, Lilja, Rock, Brux, Centermark, and several others whose names are not on the tip of my tongue tonight, all turn out great barrels. Some have a preference for cut rifled over button. Others favor a 5C or canted rifling over the standard. Most of the time it comes down to personal preference. Obviously, the 338 Edge and Shawn Carlock will forever be intertwined. He can build you a great rifle, as can most of the other gunsmiths on this site. It may just come down to who can offer the best turnaround time and price. There is often significant lead time required on barrels and stocks, so focus on those first.
I got a Brux for my 338 Edge build and will be getting another Brux when my 300 RUM needs one. I REALLY LOVE Brux barrels mine is a tack driver have not had any trouble hitting out to as far (981 yards) as my range will go.
The guys a Brux are great to work with and helped me get the right barrel for my needs.
If your gun smith does not have a 338 edge reamer and does not want to buy one. I could rent mine to you for less than the price of buying one. I have the go and no go gauges too.
Best of luck to you.
"People sleep peaceably in their beds at night
only because rough men stand ready
to do violence on their behalf." -- George Orwell --
Rest easy, sleep well my brothers.
Know the line has held, your job is done.
Rest easy, sleep well.
Others have taken up where you fell, the line has held.
Peace, peace, and farewell... --Unknown--