Three shot groups are nonsense

[ballisticboy]

When testing guns/ammunition I always use three ten shot serials fired on three different days. The three sets of results are then combined to give the overall result. But it all depends what you are trying to do.
If you are doing it to be able to boast on YouTube or on a forum then obviously the fewer shots you can get away with the better. If you are doing it to see your true dispersion on different occasions then you need to fire minimum ten round serials on different occasions.
Of course, if you are testing accuracy as opposed to group size, the two are not the same, then you need to fire groups at different unmeasured ranges under different conditions and then measure the distance of the group centre from the aimpoint. If the group centre is on the aimpoint and the group is small then you have precision which is what you are striving for.
If you are testing first round accuracy, which for most shooting is what is of real interest, then you need a single shot at different targets again at unmeasured ranges under different conditions from different positions. Of course, you cannot expect first round accuracy if you have a large group size.
No body ever said it was easy.

[RobF]

hsing-ee,

IIRC, seventeen (17) or nineteen (19) points are need for estimation of a Gaussian curve area.

Fewer data points can be used, but the error is in the estimate will be larger, so the predicted n-shot group will also be bigger.

Shooting ten (10) or more ten (10) shot groups will tell you most of what you need to know.

Have fun

Best regards

Russ

Is the right answer.

3 & 5 shoot groups mean nothing more than shooters hiding from the reality that they or their rifle is incapable of shooting more without making that group worse. It's like looking at 3 pellets and saying the whole tin is perfect.

10 shot groups are an economic test which gives you a good idea. After 20 shots if the shooting equation is performing well you're not likely to see a change.

Speaking of change, it's often useful to test over longer periods anyway to see issues that present in the field but not in 2-3 mins on a range. These are temp shift and also reg creep (if competition timing is simulated).

Takes time and effort and a desire to know the truth.

[FPoole]

I use 5 because that's what I've always read. Shooting more than 5, seems to me, would only prove the ability of the shooter. I only shoot from my knee, so it's really down to how well I'm shooting that day. I've had countless groups ruined by that 5th shot. Many ragged .25" 4 shots groups at 55 yards opened up to .5" by shot 5. I've also had hundreds of occasions where the first 2 shots were in pretty much the same hole, so I now will lobby for 2 shot groups.

[bucketboy]

If I get a nice tight 3 hole group @100m then I am happy

[Geezer]

Ten shots (or more) for serious testing of consistency and accuracy.

Three or five for a quick check or the first stage of pellet testing to sift out the stuff that won't shoot well.

Just never believe that the size of your best 3 or 5 shot groups is the kill zone that you will be able to hit reliably. It isn't. It's about twice as large, even with a solid rest.

Back when I was more serious about my shooting than I currently am, and had time, my preferred ammunition selection method was to identify five brands with potential, then set out five rows of four aim points and shoot five of each brand at each aim point in each row, benched and rested. Then check the consistency (group size) and accuracy (placement of each group). Whichever brands did best then got tested in ten or more shot groups, a preferred one selected, and then a final ten-ring zero. Then start testing and noting hold over/under at different ranges. And writing that all down.

Used to take bloody ages, though.

Now I'm more a collector and casual plinker, my regime is pick a few usually good brands, shoot some 3-5 shot groups, pick one that seems good, shoot ten, and if happy adjust POI to POA at my chosen range, then stop.

And, frankly, if the gun does OK with the first brand I try, I'll stick with it and just get the sights sorted. This would not be good for a proper serious match shooter, but if the difference between 15mm groups and 10mm ones doesn't matter to you, it is quick and effective.

[Steyr]

Serious question.
How many shots would you want to see for a gun review? Currently writing up a review for the Hatsan 200W. Was planning on a 30 shot group (compared to a 30 shot group with my TX). The idea being over an HFT course you would want 30 good shots. Too much?

30 shot in groups of 10.

you can overlay the images for the whole picture but the 10 shot strings give a better idea of the core and where the fliers are going.

overlay allows the bigger to be seen but it blurs the finer information

[Rob Edge]

People sure get a lot of flyers round here

[Muskett]

Frankly, so long as I'm shooting then I'm happy.
If I could afford it I would use crates of ammo. Don't see the point of saving ammo other than pure cost and how many you can have in your possession at one time. Only other limitation is that of using ranges and what distances you are limited too. Which is why I rarely use a range as I have open ticket on my rifles and the farm can safely do all ranges to 500m; Scotland then 1000m. Nothing better than a fine day to do a real session and really find out about what your rifles can do. Gives the confidence and familiarity in your kit to deliver humane results.
I like having a minimum good session with a rifle once a year to be happy. Thats a proper zero session. Anything less is a check test.

How many shots does it take to "know" your trigger?
Then there is prone off a bag, off a bipod, sitting, and off the sticks.
Loads to get right, which takes some application.
Air Rifles then a couple of tins is nothing. Centrefire then a couple of hundred rounds to know your rifle. Sadly, I don't do the two week shooting concentration with 5,000 plus rounds I used to do in the Army to be "shit hot".

For others its a three shot group, 1" above at 100m, off the bonnet of the truck, and that will do. That just doesn't do it for me.

[scrane]

If I'm sighting a gun in and I have three tight shots where I want them I'm done.

[Solvo]

5 shot on first pass to weed out the crap then 10.
For a final choice I prefer to shoot 3+ targets of 10 shots each for each of the top contenders.

I don't go in for competition though, so not sure I'd do this with top grade match ammo.

[Amac]

Would have to agree that five shots is a minimum for a group. That must also include any outside of the main cluster of course which cannot be ignored!

[Herx77]

Why waste ammo? Just shoot one pellet. Lets all be in the next Olympic team!

Don't shoot any, I'm as good as I want.(It does vary occassionally)
HERX77 .

[Gunfun]

I think a minimum of 10 shots or a full magazine (whichever is greater) at individual targets so you can see each individual pellets POI.
One main advantage of airguns compared to powder burners is POI/accuracy does not change due to the barrel heating up so shooting 10+ shot groups really pushes this small advantage home.

[Solvo]

Bloke on the range did a good youtube vid explaining why 3 shot groups are useless:
https://www.youtube.com/watch?v=4dhPTf18_mw