Looking for someone with experience here, not a Hazard ID form. Not to seem disrespectful, although it'll likely get taken that way anyhow.
A little research puts a few opinions forth that the bullet for the service load for 8mm was 196 grains. 220 grains is pretty close to that... I have not shot a Hakim yet. I have shot
( and reloaded for ) Mausers plenty in 8 x 57 mind you...different animal though of course.
As to the 8 x 64 ammo...well a loaded cartridge is cheaper than 8mm bullets alone are...so, yeah...I want to utilise them if at all possible. It's stupid easy to dismantle them too. Given the choice of heavier vs lighter than service load; cautiously I prefer heavier. These guns were meant for service loads, not powder puff CASS loads. I don't want to abuse it, but still run a decent load.
Burning though Premium bullets shooting plates does seem a bit costly.
Seems like I'll need to do some research and dig out the Chronograph, find a loading with a decent velocity and carefully see what works. Unless someone has anything real world in this ballpark to add.
Self Isolation is much better when firearms research is possible.