my last Winchester shot a 129g Hornady Flat base Interlock with 61g of IMR 4831, Rem brass, Rem 9 1/2. I have no idea of the speed, but the killing ability of this load proved to be incredible. The bore got to where it looked like a pitted sewer pipe, but still shot this load great, but I had to de copper the barrel every 12 shots to keep accuracy.
6.5 PRC has the same case capacity of the 264 Win Mag if you are into the latest and greatest kind of thing.
H1000 is a game changer in barrel/throat life of the 264 Win mag, those with ears, let them hear!