When I am working up a load I begin by loading several rounds in half or full grain increments, depending on the size of the cartridge case, to determine the maximum load with that combination of components. I weigh my cases, bullets, and powder charges at this stage to ensure that the results are not muddied up by velocity spikes or drops produced by out of spec case volumes or bullets which are too heavy or too light. To my way of thinking, it is better to determine the maximum load and work backwards from there to find the best accuracy.
I fire these rounds over a chronograph, and I consider the load is maximum when the velocity plateaus. This plateau is easy to spot as long as you begin 5 increments below maximum. Once the plateau is observed you can be sure that sticky extraction is only a round or two away.
Once my maximum load has been determined, I then check this load for consistent velocity by firing a 5 shot group across the chronograph. This is for consistency only, so I am not all that concerned about results on the target. Should the load show good consistency I will check the accuracy at 300 yards to ensure the accuracy that was promising at 100 yards hasn't gone south. I may fire several 3 shot groups at this range or longer ranges if time and ammo permits. These 3 shot groups are made with no allowance for barrel cooling.
If the load proves consistent in velocity, and if it groups within my expectations I consider it to be a good hunting load. At that time I might shoot it over various ranges to record the bullet drop, and compare the real bullet drop to the drop predicted by the computer program. I seldom shoot a hunting rifle from the bench, but if I do I also make sure I shoot from field positions to ensure there is no shift in POI.
If the load is going to be shot in a target rifle, particularly if it is going to be a long range load, I will fire 5 shot groups of the loads that are within the velocity range I am looking for. My target rifles are always fired supported both front and rear. Those that group well at 100 I will test at longer range, 500 yards is convenient, but 800 yards+ is where the loads will have to perform. While I prefer to allow time for the barrel to cool between shots, if the day has variable conditions I will shoot the groups quickly. I generally clean my barrels, both target and hunting barrels every 50 rounds, although there have been exceptions.
