3 shot groups are what most guys use, it gives you a good idea for tuning, does not over heat the barrel, easy on the shoulder and so on. Like mentioned it will help to eliminate "Chasing of the Bull" on your range sessions, not to mention help reduce wasted time, effort and ammo.

It is highly possible your rifle does not like the loads your feeding it you can try a different manufacturer, style or grain size for comparisons.

Good Luck