Are you trying to see what the gun is capable of, or to improve your accuracy?
If you're testing the gun, shoot it off a rest, or see if you can borrow a ransom rest.
If you're trying to improve you own accuracy, there are a bunch of ways to go about it, so I'll stick to what I know.
I shot on the MC pistol team and we started by firing on a blank target to hold 8 ring sized groups. Once you shot two of those in a row, you moved on to shooting at the B8 .
Once you had 2 in a row that kept all of them inside the black, you started shooting for 10s. Two in a row all 10s at 25 yds and you moved back to 50 and started over again.
I found that going for consistent results, as opposed to trying to achieve a certain score, made for better results.