had one years back used 270 win brass .loaded 54.0 4350 IMR with140 sierra MKHP.prone gun onS&L action at 1000yard in PA. have a SAKO L57 sporter chambered in 6.5 -06 standard shoulder ....GEORGE
I have had several 6.5-06AI and all have shot lights out with 59 grains retumbo, fed 215 primer, Lapua brass, and a 140 Berger. Average velocity out of a 26" tube has been about 3070.
Most of the ones I have built will shoot 60-60.5 gr of Retumbo and 140 Bergers into little tiny groups. I use 215M primers. My reamer has the 140 seated out a little farther than normal, so work up to this load. 3050-3150fps depending on barrel length.