How many shots in a group to sufficiently demonstrate precision?

[Centercut]

EDIT: originally topic said accuracy. It should have said precision... This seems to be a hot topic these past couple of weeks... I've seen 3 shots, 5 shots, ten shots and some even said 10 ten shot groups. I even posted a while back where I said I'd like to see 5 or 6 five shots groups shot consecutively, no cherry picking... Below is a photo that I've posted on here before, shot at 100 yards with my .22 EDgun R3 Long, 25.4 grain JSB RD Monsters at 925 FPS. Its a seven shot group to the best of my memory. So look at the order it was shot. If I'd have stopped at 3, I'd have had a 1/2" MOA "group". As it is, C to C is exactly the same size as a quarter, whatever that measurement is... Slightly over an inch? No ruler or calipers in front of me. So does my gun shoot 1/2" MOA or just over an inch MOA? I think my point is that every gun I own will shoot MOA when using a 3 shot group at 100 yards, but only one (my .30 FX Bobcat Mk2) will shoot under an inch 5 shot group repeatedly and consistently at the same distance. What do you guys think?

 

[DonC]

My club BAGA has a interesting 50 meter target for competition. We shoot 5 groups, each group is 5 shots for 25 shot total. It' a lot of fun and divisions for all diciplines.

Results are really empirical.

 

[Motorhead]

I have always rated my FT guns at 50 yards and in 10 shots. While any groups shot become subjective after the FIRST due to hold and stability issues etc ...

Added to the fact ACCURACY is a combination of many factors at play .... to make claim my gun is accurate is actually stating YOU and said GUN are accurate together because seldom will another person shoot any stated accurate gun as well as the person making the claim.



Just my take on it.

Scott S

 

[Brian10956]

I think when manufacturers talk about the accuracy of their guns they do the test under ideal conditions , no wind, gun is held in a special apparatus and the trigger is pulled electo-mechanically. 

I find that just about all of my rifles are capable of shooting tight groups what I work on is getting into a zone where my breathing can be controlled. Over the last 2 years I have had a irregular heartbeat problem when that is happening I can’t shoot consistently but when it’s under control I can shoots the nuts off a squirrel. For accuracy I find using weight sorted pellets to be the most helpful. I’m able to use most of my pellets as I will make adjustments when I switch from 1 weight batch to another 

 

[DeutschKSK]

Army standard is 3 shot groups.. what I usually use. 

 

[Greenarrow]

I think many of the guns we shoot are capable of MOA, even better. It’s the shooter and the conditions that are the largest contributing factors to less than (greater than?) MOA results. At least that’s what I observe with myself. Anyway...



My opinion is at least 5 shot groups for 3 groups to show what is average for the shooter, in current conditions, with a particular gun. There is no science behind what I just said, just what I feel would show what is possible with what I have experienced in my backyard airgun adventures and reading others experiences online.



Maybe we we should make push to make 10 shot groups the “acceptable” standard??? I’m all for it! It means I’ll get to shoot more!

 

[JamesD.]

You should consider entire shot string. If it’s regulated or not. If you’re sorting & weighing or not. Are you a hunter or a competitor? Average all of your groups & there you have it. It then depends on if you’re happy with that. I’m a group shooter but it’s the 1st & only single shot that matters most to me. If it, or 10th is a flyer or my fault, average it in for real world claim.

 

[edosan]

My thoughts

3 Shot Group for firearms: is understandable due the price of the ammo and the speed, is not really affected by small wind changes up to donno 200y?

5 shot group @ 100+ yards outdoor is fine for airguns, any wind change will affect accuracy much more than firearms, so the longer it takes (more shoots) externals comes in to play

10 shot group indoors or in places not affected by the wind

 

[dan_house]

5 shots in a group, five groups on the page/sheet, or 5 target cards (like the Gamo targets)

But include date, time of day, altitude, weather conditions (humidity, barometer, temp all of which my fone will tell me for my immediate location) and pellets if shot outside. Temp and humidity likely enough for indoors 



But dont be surprised if the interweb calls bull.....

 

[elh0102]

Statistically, I think it makes no significant difference. Much more important is the number of total shots fired. If you shoot 50 shots, either 10 5-shots groups, or 5 10-shot groups, the accuracy of a rifle/ammo combination should be reasonably demonstrated. Five shot groups are the most widely used, and it is therefore easier to make comparisons. 

 

[Airmanator]

3 shot is cheery picking. Why not 2 shot groups or 1 shot group? When I group, I used empty my magazine. That means 10-16 shots group. Depend on how much the mag holds. But nothing less than 10. So I get an understanding how my gun is shooting. 3 shots under .5 inch at 100 yard is possible. But to do that with 10 shots, the gun and person shooting it must be in harmony.

 

[Hairsmith]

Back when I read Ned Roberts book ( Muzzle Loading Caplock Rifle ) I found it interesting that many times the standard was 50 or 100 round groups. These were black powder muzzle loading rifles. So a group might take most of the day. Tomorrow we will change the powder charge five granes, then next weekend we will try thicker patch material. Or at least that is how I think the conversation went.

i have shot a few groups that were an entire shot string with PCPs. One was with my regulated 12fp AA S200 so right around 60 shots. Every time I do something like that it is a humbling experience. Not only does wind and weather come into play, on top of pellets, condition of the barrel. But also, concentration. But I end up with a pretty good feel for how that gun shoots and how I shoot it. 

 

[Brislee]

I do most of my group shooting offhand (springers don't like to be shot off a bag) so 3 shots at any distance that touch...I quit while I'm ahead.

Above shot last week @ 20 yards offhand FWB 124 w/ scope on 12x

 

[elh0102]

I think a couple of different things are being mixed into the discussion. The OP's question regarded how to best determine the accuracy capability of a rifle, not to determine how well one can shoot. So the first assumption is a solid bench rest or or fixture. In the original target shown, attempting to reach any conclusion from either 3 or 7 shots is of no merit. Anomalies occur randomly, but will repeat at some general interval. IMO, you must shoot enough total shots to minimize the effect of these random anomalies. The averaging effect of a large population will help in that process. Of course, uncontrollable variables sometimes bite us. I have had barrels that would not shoot 50 rounds without lead fouling to the point of affecting accuracy. What to you do, call time out and clean? It can be complicated. But, I am totally convinced that most claims of supreme accuracy are based on insufficient data.

 

[Brislee]

While my above post was sorta tongue in cheek, whether you shoot 3 shot groups or 10 shot groups (or more) the accuracy of any gun will ultimately always depend on the ability of the shooter . 

 

[elh0102]

While my above post was sorta tongue in cheek, whether you shoot 3 shot groups or 10 shot groups (or more) the accuracy of any gun will ultimately always depend on the ability of the shooter .

I understand and appreciate your point, but I think it is a totally different topic than the OP has questioned. Given comparable rifles (or, the same one), a better shooter will, on average, do better than one of less ability. No argument there. Yet each rifle does indeed have limitations, so, you can flip your position around. Give two shooters of comparable ability rifles of significantly different performance quality, and the one using the better rifle will win. If you are shooting for score and your rifle isn't capable of shooting groups as small as the 10 ring, then a perfect hold will still suffer flyers and a lower score. Your point is well taken, as most shooters cannot utilize their rifle's capability. But, the best shooters can, and their equipment is put to the test at every match. 

 

[Scotchmo]

It's a statistical problem. Use whatever number of shots gives you a sufficient confidence level. You determine that.

For a given system, if the standard deviation from POA is 1/2moa, then there is about a 32% chance that the next shot in any group will be outside the 1/2moa. And there is about a 5% chance the the next shot will be outside 1moa. When taking more shots, the group can only stay the same or grow larger, but that larger group does not mean it is less accurate.

When testing for actual accuracy, I like to shoot individual bulls, like in benchrest. Measure each shot. The SD from the POA is the accuracy.

 

[bubblerboy64]

It depends entirely on what you are looking to accomplish. I like to long range groundhogs. IF???? I could shoot one shot out of my varmint rifle and hit a six inch gong at 400 yards and then take another shot at it and hit it again (and do this repeatedly day after day) I’d be happy. I really don’t care what the next three to seven shots are going to do because I’m not going to get that many shots at groundhogs. But I’ll wager if the first two hit most of the rest will as well.

Shooting groups beyond that is mostly a test of the shooter not the gun.

One of the madding things is guns often don’t shoot the first shot into the group. So what do you do then? 

Some of this has come from my experience. I used to shot a lot of groups in the course of reloading and I will tell you FOR ME about the time I’d think I was onto something with a load the next range session that load that shot great the week before today was just back to being average. 

If I can shoot three shots into 1/2 inch at 100 that’s my load I’m not going to burn money and barrel life looking for that tiny bit better you might ? get

Doesn’t mean someone else shouldn’t. 

I’ve seen so many people post a five or a ten shot group and call a couple fliers their fault. If you are going to do that what’s the point. Just shoot the three and put your gun away. 

I think the number of shots is based on competition. How many shots in a match.

What we are looking for is consistency. I feel after 40 years of shooting I don’t need to shoot all that many shots to have a real good idea of the how the gun and ammo is going to do., now if I was buying a gun to compete with then I’d want to see how it would do in match conditions so a couple ten shoot groups a good idea. 

Short answer. All depends 

 

[boscoebrea]

Always 5 shoot group to see,then if it looks OK,I shoot until I can't tell where pellets are hitting then start another group.

For testing pellets it does not take many shoots to tell if pellet works in gun or not, certainly not more than 5 shoots.....

We use five shoots offhand because 1,concentration,muscle fatigue and breathing....

Another reason 5 shots , "back in the day" you did not want your 6shooter to have the hammer on a live round....until ready to fire.

 

[bubblerboy64]

Five shots out of a six shooter. Learned something. Might not be correct but seems reasonable.

I’m most impressed with someone who can make the first one count. I struggle with that. Give me a couple try’s and I’ll hit but. The guy that can pull the gun out of the bag use his rangefinder and wind thingy and dial the correct info into the scope sit down and onnect with the first one . Now that impresses me. Or the guys that can shoot off hand .