I have a Brno 21H and a Sako M85 Bavarian in 7x64. I really like the cartridge.
Both rifles have throats so long that a 160 grain bullet is almost entirely out of the case before it touches the rifling. As a result, factory ammo can be somewhat lower than expected velocity and hand loads can be a grain or two higher than some data would indicate is a "max" load. Max length is determined by the magazine in my rifles, 3.3" or less. Accuracy in both rifles is good, around 1-1.5" at 100 yards without taking very exceptional care in the aiming. I see you are in the USA. Load data with common USA components is not easy to come by in North America. The Hornady manual actually lists data for the 7x65R, but shot in a bolt action - not the 7x64. I think they made an error - a rimmed cartridge in a bolt action repeating rifle is almost never done - so I don't really trust their data. I don't think the Lee load manual data is worth looking at either, all they did was use 280 Rem data and reduce the recommended loads.
My two favourite hand loads are as follows:
Norma brass, 57 gr. VV N160 powder, 160 gr. Nosler Partition, Rem 9-1/2 primer 2850 fps ( Vihtavuori published data max. is 57.3 gr and 2900 fps) Accurate, fast, & deadly.
Remington brass, 56 gr. IMR 4831 powder, 160 gr. Speer GS or BT or 160 Sierra BT, or 160 Nosler PT or Accubond. Rem 9-1/2 primer, 2850 fps
This load was developed by me with the experimental "test and try" method, and is perfectly safe in MY rifles. Remington brass is a little heavier ( thicker ) than Norma. ( RWS brass is even thicker/heavier hence less capacity) The same 3 Remington cases were used in max. load safety testing and shot/reloaded repeatedly with no sign of excess pressure and primer pockets still tight after 10 times shot/reloaded - but please work up in your rifle from a few grains below and watch for over pressure signs. I can use one more grain of powder in Norma cases and probably would use one less (55 gr) in the RWS cases, but testing continues with RWS.