Not being a smartass, only asking out of ignorance - can someone explain why a 10 shot group makes any sense?
Short answer is to increase your hit probability.
I will explain this the best I can. The first thing you have to understand is guns shoot in cones. Exactly the same as a MOA or MIL is setup. the means that in a 2d world on your target your rifle will shoot into a circle.
Some guys such as myself that are dabbling or profiecient in the long range world want to know our probability of a hit. This is based on a couple things, Target size and cone size of your weapon. The goal is to increase the probability of a hit to as near as 100% as possible.
3 in the statistical world is nothing. 3 isn't enough to draw a conclusion. The sample size is just too small. 10 of something is getting some where. 30 is better. Most guns can manage a 1" 3 shot group accidently a couple times.
What you trying to figure out is what can your gun do ON DEMAND. Not once here or once there if "you do your part". What can you drop down and shoot right now.
So what your trying to figure out is what you ENTIRE weapon system is capable of. Gun, Scope, Rounds and Shooter.
Below is some of the variables that happen when you pull the trigger that make a gun shoot into a cone.
Lets start with the gun you have a barrel. The bullet wont jump the same way everytime from the casing to the lands to continue down the barrel. Also the quality of the rifling and the speed (twist) of the rifling come into play. So does the barrel harmonics. There are some other things I'm going to skip over, Its just too much to type. free floated or bedded barrel. bedded action. stock rigidity. Stock action screw torque, this relates to action and barrel harmonics. Also heat and was the barrel properly stress relieved. barrels shouldnt move their point of impact when they are hot. but many do.
Then you have your scope. Does it hold its zero through repeated firing or does it move tiny amounts. I had a couple vortex on some guns that I couldnt get to group better then 2" 10 shot groups. Many 3 shot groups were touching but together it looked like buckshot. The scope was moving tiny amounts with every recoil. I put a nightforce on the gun and my groups shrank 50% with that one change.
Then you have your bullets. The BC on a bullet has some variable from bullet to bullet withing the same lot. Its small amounts but its there. So is variance of the bullet weight. So is variance in the brass weight. Then there is variance in the primers. Then you have your ES and SD of the round. All this goes back to and can be influenced by your barrel twist and length. No two bullets are exactly the same.
Then there is you as a shooter.
You add all these things up and your gun doesn't shoot exactly the same every time you pull the trigger. Thus you point of impact falls into a cone. The easiest way to determine that cone size is just to shoot some groups. You can shoot 3 shot groups if your barrel gets hot and goes to stringing. Stop. let it cool then shoot 3 more. But shoot at least 10 shots to the same target at the same time. This allows you to make sure your cone is centered over your point of aim. This is also a baseline for how accurate your gun is to start. Also during this time if you have a chrono that doesnt attach to the gun you can chrono 10 shots and see what your muzzle velocity and ES, SD are. With having your velocity you can input that into you ballistics calculator and with your point of impact (POI) directly overlaying your point of impact (POI) you can go verify your gun at range for your drops.
I'm sorry I know this response is very wordy and much more then you asked for. But this is a semi complicated thing to understand and there isn't just a short answer other than to increase your hit percentage.
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