I know someone who just built one and its impressive. He is using the 6.5-300 WSM
Version which is pretty much the same. He is shooting the 139grn Lupa Scenar (BC .615) and 140grn A-Max (BC .550).
His rifle Has a Krieger 30", 1-8.5 twist barrel and he is using 71grns of Retumbo. He informed me he is getting 3500fps with this set up. He is using Norma 300 WSM Brass and Federal 215M Primers. He had the rifle built for varminting out to 1500 yards.
Hope his helps!