Hi Elvis,
Yes, I have a 6.5x57R drilling, and the case does have about the same capacity as the 6.5x55.
When I bought my drilling, part of the deal was some factory Hirtenberger ammo loaded with 120-grain bullets, which chronographed around 2800 fps. I decided to try AR2209/H4350 with slightly heavier bullets, starting with the 125-grain Nosler Partition, working up to 45.0 grains, which shot very well at a velocity around 2750 fps. Have since tried the same load with two 129-grain bullets, the Hornady Spire Point Interlock and Nosler AccuBond Long Range, and it work fine with them as well, though the muzzle velocity with the Hornady was somewhat lower (they tend to result in less pressure than other bullets). The drilling's barrel is 23.6 inches long (65cm).
No doubt the powder charge could safely be pushed a little higher in a bolt-action, though even at 2750 the 6.5x57R kills very well.
John
