I test a pistol the same exact way I do a rifle. I load up my test rounds in .1 grain increments, and shoot them as accurately as possible at 25 yards. I have found your pistol will shoot certain loads better than others, just like a rifle. I tested my G35 in 40 cal this way. I am in the middle of testing both my G20 and G29 in 10mm with the new Lone Wolf barrels I just installed. When testing, I shoot seated from a bench, I rest my forearms on sandbags, and concentrate on a perfect trigger squeeze and sight picture. I normally shoot through a chonograph to get velocity readings also. Each test load will have it's own aiming point or 3" shoot n see to know which group is which. I normally test at 25 yards.