How do YOU measure group size?

[milrifle]

So how do YOU measure group size? Sure, it's easy enough to just measure the extreme spread. But what about those pesky flyers? Do you just throw those out like your 8th grade math teacher used to to do to your lowest test grade? That's hardly honest now is it? Including them isn't really fair to yourself though. Say you shoot four rounds you could cover with a quarter, then that fifth one goes 5 inches away. Is that really a 5" group? Well yeah, I guess it is, but...... should it have the same weight as the others in calculating group size? It doesn't seem like it should.

So how many of you calculate average group radius? That seems like a fair way to do it. You don't throw out the flyers, but then again, they don't count as much as the other rounds that are tightly grouped together. It takes a little work to do, but I think I'm gonna try it.

What do you guys think?

[tomme boy]

I count the fliers. They are there because of a reason. Just have to find it.

[HARRYMPOPE]

I shoot three or so at a separate sighter target then shoot 4 consecutive 5 shot groups or two consecutive 10 shot groups.It gives a good idea of how the load is.Shooting one 5 shot group of a load and comparing to one 5 shot group with another small change is not a safe bet to evaluate one load against another.

george

[Idaho Sharpshooter]

Offhand or Bench, pistol or rifle?

[RetAFSF]

I re-shoot the group. The flyer is a shot outside the expected standard when compared to the other four rounds and is 99.9% of the time caused by shooter error. If it were a perfect world in the reloaders/shooter relm you could actually place all bullets in a single bullet hole. In reality there are too many factors involved for it be possible, we can come awful close. So blow off the flyer and shoot another 5 shot group, just employ all basic shooting fundamentals and try it again. My python is capable of 1/2" groups on one of my better days. Generally I end up with flyers with the .38 is because I shot the .45 or .44mag first opposed to starting with the least powered caliber first.

[Jack Stanley]

I count the fliers. They are there because of a reason. Just have to find it.

I'm with tomme boy , particularly if I am working on an all purpose load . No matter if it's hot or cold sunshine or snow I want the first and all the rounds after that into a group I can count on . My bragging groups aren't as small as others because I'm still looking for the reason that flier went out from the rest . It will drive ya over the edge sometimes

Jack

[Hip's Ax]

It depends, if I know I shanked that shot I leave it out of the group. If I didn't, I leave it in. Frankly for my final test I'll shoot 20 rounds of the apparent winning powder charge at the correct target at the specified distance in position. If I've got say, 17 shots in a nice group with 3 unsociable fellows I call it good because I can easily imagine that in prone from the sling I do not always execute perfectly.

[bob208]

to think of all the more matchs i could have won if i could have throwed out the wide ones.or even reshot the target.
another way to measure is by string measure.

[fatnhappy]

I use the internet method. I measure between the widest two shots and then report half that distance.

seriously though, flyers are part of load development and need to be accounted for. There's something wrong that requires correction.
Called flyers from botched shooting technique are something else all together.

[fouronesix]

I measure center to center between the farthest holes. Usually five shot groups. I enter the group size in my load data log along with mean velocity and standard deviation of velocity if shooting thru the chrony. The data becomes valid after a few repetitions during subsequent trips to the range.

[220swiftfn]

To the OP, as stated above, count them all, and if there's a reason that ones out (called flier) make a note of it. (If it makes you feel better, have two group measurements, overall and best three.....)


Dan

[Larry Gibson]

I measure extreme spread because it is what is common used these days. I discount a "called shot" if I shoot another in it's place. A "flyer" is always ****ed as it is telling you something about the load. BTW; 3 shot groups are just nice (that's about all you can really say about them), a 5 shot group will give you an idea of the loads capability (accuracy, pressure and velocity), with both the groups size is very subject to "random dispersion". A 7-8 shot group is the minimum to get any statistical validity to the group and assurace that the accuracy, velocity or pressure is what can actually be expected. SAAMI requres 10 shot test strings/groups for validity. I use 10 shot test groups for such testing also.

Larry Gibson

[TNsailorman]

I really don't care whether the internet tells the truth or not or how it measures its groups. When I shoot a rifle or pistol for group, it is to test that firearm or load to see what it is capable of shooting. Therefore, fliers get counted in every group I shoot. I shoot more than one group when testing either ammo or gun and if I have three groups that are without significant fliers and 1 that does, I assume shooter error and take the results of the 3 groups that are flier free as the base. Most experienced shooters know at the moment of trigger release if they have "pulled" one or indeed if they were "dead on", so a flier rarely catches them by surprise. And yes, I have seen some real "whoppers" appear in posts but then my load or firearm isn't affected by those, so it really doesn't concern me too much one way or the other. It is just a matter of being honest with thyself pilgrim. I'm just getting too old to care what the world thinks. james

[357maximum]

I count all the shots in my final workup groups...usually 10, measure the farthest distances edge to edge then subtract the boolit diameter. If I feel one of the outlying shots was MY FAULT I simply repeat the test to confirm.

If I am doing preliminary workup I normally only shoot 5 rounds and they all count as shots.

My favorite "hunting" group testing method is to shoot one boolit every morning/evening for 5 or ten days. This is what counts for a hunting gun/load. It may take me 2 weeks+ to make a 10 shot hunting group depending on schedule. This method is only used on loads that I feel really really good about. I try to do it with every gun I plan to hunt with. I normally succeed, but every now and again you get a stubborn subject.

[303Guy]

If I get two shots 'touching then I call it good and claim my rifle and load shoots holes that touch! Nah. But a mate of mine does.

I look at shot probability. 50%, 75% and 100%, the latter being worst case and include 'flyers'. If the spread is even I say that's the group size. When there is a 'group within a group', I use the 75% probability and make allowance for the worst case and see what I can do to identify the cause of the 25% 'outside group' shots.

Three shot 'groups' are nice but only when they tally with ten shot groups and must therefore form a triangle. Useful for readjusting sights.

[williamwaco]

I count the fliers. They are there because of a reason. Just have to find it.

Ditto.

But!

If I pull a real boo-boo - Jerk the trigger, touch it off before the sights are aligned, stock slips on the bag, something like that. I ignore that shot and re-shoot it. I call that a "miss", not a flyer. It is then a six shot target but I count only five of them. And - uh-uh, not the "best five" but the five good ones.

[Blammer]

I shoot once, and therefore my rifle is a one hole shooter.

for pistols this is how I measure group size.

[Blammer]

These are 5 shot groups.
On the top group, I burped.

on the bottom group, I hiccuped.

[Griz44mag]

You gotta count them all, then find the reason for a flyer.
You can't get the deer to stand still while you figure out why you missed the mark.
Work at it til you have no flyers, that means ammo AND shooting skill.

[303Guy]

You gotta count them all, then find the reason for a flyer.
You can't get the deer to stand still while you figure out why you missed the mark.
Work at it till you have no flyers, that means ammo AND shooting skill.

I have to agree with that. However, knowing what your rifle does helps establish the range at which one can take a shot or the size of the target one can shoot at a particular range.