As Txhunter58 and others have mentioned, 5 grain amounts is the standard work up. A word of caution, when working up your load do not be too quick to adjust your sights. Many rifles have a break in period of time until they start to shoot a consistant group. During this time all the burrs and ruff spots seem to wear out of the barrel, then it starts to produce the sweet loads...

I also shoot groups at each level only I do a five shot group. I shoot five rounds and if I know one of the shots was not my best effort, then I do a six shot group. I want to see a nice tight group before I decide whether to move the powder charge. If your shooting a string they claim to add a few grains if your shooting a flat line then reduce a few grains... according to the old timers that taught me...