Accuracy vs. precision

[daniel craig]

When shooting, accuracy and precision can go hand in hand OR they can be mutually exclusive.

You can have accuracy without precision and precision without accuracy.

Accuracy describes the difference between the measurement and the part's actual value, while precision describes the variation you see when you measure the same part repeatedly with the same device.

It helps, when talking about rifles to understand what is going on here.

If you get a tight group you’re looking at precision. If that tight group is far from where you aimed that would be high precision but low accuracy. It’s the difference between the two that can frustrate a new shooter trying to sight in a rifle.

Let’s say the shooter takes his brand new rifle to the range, and from a standing position touches off 4 shots. When he examines the target he notices that none of the holes are close to each other nor are they close to where he aimed. The new shooter probably thinks he’s looking at poor accuracy when in reality he is looking at BOTH poor accuracy and poor precision.

A little annoyed the shooter takes up a prone supported position, and touches off another 4 shots. Upon examining his target he sees that all the holes are touching but not where he is aiming, this is an example of high precision but low accuracy. It show’s the shooter that he has the fundamentals down and that he just needs to adjust the sight/scope.

If, on the other hand, the shooter takes up a prone supported position, fires four shots and gets them all within the the second smallest ring but none of them are close to each other he has achieved accuracy but not precision, and chances are it’s not the tool he’s using but a hang up in one of his fundamentals.

Most rifles will generally shoot where you point them, the limiting factor being your ability to point it and keep it pointed where you want the bullet to go.

If you can only have one or the the other, take accuracy every time. It might not be as pretty but if you’ve got limited time to train and a limited budget, training for relative accuracy (as opposed to both high precision and high accuracy) will be more worth your time.


Edit: the intent here wasn’t to call anyone dumb or take a “holier than than thou” position. I like talking through concepts, and trying to explain them helps me see if I understand the concepts correctly. I’m not saying that you do is wrong or that you should change how you’ve always done things.

 

[rkittine]

Nice explanation. When I shoot 1,000 yard bench rest, I need precision and accuracy, but in 100 yard bench rest it depends on whether you are shooing Group or Score. You can have a great score with a mediocre group or a tight group with a poor score as the group is in the wrong place.

Bob

 

[LiveLife]

To me, accuracy is producing smallest groups compared to precision is producing consistency of group size despite differing conditions of ammunition and temperature of barrel.

So, while an "accurate" pistol or rifle with match grade ammunition or handloads can occasionally produce small groups (Say 1" groups at 25 yards for pistols and 0.5" groups at 100 yards for rifles), this capability may not produce average group size consistently with extremes of group size being 2.5"+ for pistol and 2"+ for rifle with various commercially available ammunition or reloads.

But a pistol or rifle with "precision" with similar ammunition may produce more consistent average group size with smaller extremes say no bigger than 2" group size for pistol and 1" group size for rifle. So I would consider firearm that produces more consistent average group size having greater "precision".

Another example is a thinner barrel AR that is "accurate" with cold barrel to produce 1" groups but after couple of magazines, will produce 3" groups to me is considered accurate but not with practical precision. In comparison, AR with heavy barrel could produce accuracy of 1" groups with cold barrel but after several magazines continues to produce 2" groups to me is both accurate and with practical precision.

Another perspective is I like point shooting option for defensive purposes and there are "accurate" pistols that can produce smaller groups under sighted slow fire conditions but I prefer to have carry/defensive pistols that can produce consistent groups at natural point of aim even under unsighted point shooting with fast fire/mag dump shooting conditions and I would deem these pistols having reliable "combat precision".

 

[daniel craig]

To me, accuracy is producing smallest groups compared to precision is producing consistency of group size

That’s literally the opposite of their definitions. See above.

 

[aarondhgraham]

Way back in time when I used to teach archery,,,
This was the toughest concept to get across to newbies.

One person would hit the 16 inch target every shot,,,
But the arrows were all over the place.

Another person would hit the dirt in front of the bale every shot,,,
But the arrows were clumped closely.

The person who was all over the target would need a lot of help,,,
Draw length, nock position, release, etc, would all need work.

The person who hit the dirt was actually doing better,,,
All we needed to do was adjust his aim.

On the rare occasion when I get to teach a newbie with a .22 rifle,,,
I always have them start shooting with a front rest and rear bag.

When they ask me why I won't let them shoot standing/off hand,,,
I tell them I'm trying to lessen the effect of the many variables in off hand shooting..

My goal is to get them to shoot a tight group,,,
More than anything to convince them that it is possible for them to do so.

Then and only then do we work on off hand techniques.

Movies and TV has given people very high (read outrageous) expectations,,,
Most people I have introduced to shooting think they should be able to hit a coke can at 100 yards with every shot.

I once had a friend who bought a .22 rifle for his son,,,
He thought the kid's rifle was defective because he (not the kid),,,
Couldn't hit a coke can at what had to be somewhere in the vicinity of 125 yards.

Aarond

.

 

[daniel craig]

Movies and TV has given people very high (read outrageous) expectations,,,

Especially when it comes to pistol shooting

 

[LiveLife]

That’s literally the opposite of their definitions. See above.

Well, I did post "To me" as I am not an expert on such matters ...

OK, maybe this better explains accuracy vs precision as illustrated by various 22LR matches we had on THR:

• Accuracy is being able to produce holes closer to the center of target (point of aim)
• Precision is being able to produce smaller groups even though holes do not come close to the center of target (point of aim)

So on our various THR 22LR matches, tighter groups that produced holes away from the center of target produced lower score than larger groups that were scattered around the center of target.

Is this better?

 

[Bwana John]

Is this better?

Yes

 

[LiveLife]

Yes

Don't get old ... or you get the rambling jumbled brain syndrome.

Oh my, I think it's time for my afternoon nap.

 

[Bwana John]

Don't get old ...

While I can't do anything about the getting old thing...

They can't make me grow up.

 

[Craig_AR]

Every repetitive physical process has a natural variation in results due to the many factors affecting the outcome. That variation results in the level of precision of the process. Setting artificial rejection rules for the results without looking at the natural variation first can result in high rejection rates. Setting a goal result without understanding the centerpoint of the range of the variation is a misunderstanding of the natural accuracy of the process. Changing the process to first reduce the natural variation (precision) to a desired level, and then to center the variation around the goal result (accuracy), is the core concept of quality manufacturing as taught by Dr. W. Edwards Deming, the academic statistician who saved the economy of a nation. I had the privilege of being one of about 1,200 Defense Department workers, mostly in uniform, for the Deming Seminar in 1988, in a hotel across the highway from the Pentagon.

One of his demonstrations of adjusting to first bring precision, then accuracy, was dropping ball bearings down a funnel into a sand bed, marking where the balls hit over a series. The resulting images of the results were a perfect example of the training on firearms ranges every day, looking just like the targets on the ranges: get your grouping, then move to the bullseye.

I was surprised that Dr. Deming never pointed that out, either in the class or in his book, especially in a hotel conference center full of GIs. Of course, his background was university academia, and industrial production consulting, especially in the automotive arena.

Maybe ole Sarge the Rangemaster really was just as smart as the professor.

 

[daniel craig]

Well, I did post "To me" as I am not an expert on such matters ...

OK, maybe this better explains accuracy vs precision as illustrated by various 22LR matches we had on THR:

• Accuracy is being able to produce holes closer to the center of target (point of aim)
• Precision is being able to produce smaller groups even though holes do not come close to the center of target (point of aim)

So on our various THR 22LR matches, tighter groups that produced holes away from the center of target produced lower score than larger groups that were scattered around the center of target.

Is this better?

Lol yes and it’s literally the spark notes version of the Original post.

 

[LiveLife]

Lol yes and it’s literally the spark notes version of the Original post.

Wife keeps reminding me that power naps in my retirement is essential to my well being, for her sake.

Maybe ole Sarge the Rangemaster really was just as smart as the professor.

During boot camp, I was discouraged when my M16 holes appeared top right of center of target.

To my surprise, drill sergeant smiled and said I just needed to adjust my sights and presto, I was shooting to point of aim. Not bad for Vietnam era M16s with almost smooth bore barrels.

 

[H&R Glock]

Sounds like Jeremy Stafford's article in the August issue of Guns and Ammo.

 

[denton]

Daniel craig and Craig_VA have it right. Accuracy is how far from the mark the center of the group is. Precision is how tight the group is.

Deming probably knew well how to shoot. His BS was from University of Wyoming, at Laramie. He later did his PhD in physics and math.

 

[daniel craig]

Sounds like Jeremy Stafford's article in the August issue of Guns and Ammo.

Maybe it is. I don’t get that magizine but I do have a science teacher and shooter for a dad lol.

 

[Bfh_auto]

That’s literally the opposite of their definitions. See above.

This is like the clip vs magazine. The ones who don't want to get it right won't.

 

[buck460XVR]

This is like the clip vs magazine. The ones who don't want to get it right won't.

Funny how the internet makes everyone an expert nowadays. It amazes me how everyone on Facebook is now a Virologist. I can Google, so now I am an expert. One only has to read a few threads on any gun forum to see folks, for the most part refer to their guns and ammo as accurate. Precise is very seldom talked about. Groups of less than 1" MOA are considered accurate. Guns in general, from my life experience with them for over half a century is that they are considered accurate or not. Like the clip thing, life is too short for me to get my undies in a bundle because someone thinks they are the self appointed Grammar Nazi for today. If you want to bicker over the small stuff and talk down to other wise responsible gun owners.....so be it. Not my priority.

 

[mcb]

Except accuracy and precision have widely accepted definitions that are common across a wide range of engineering and scientific professions including those that include ballistics. These terms are not niche terms relative to firearms only, like clip vs magazine. Pick up a text book on Ballistics or one on Geometric Dimensioning and Tolerances or one on Experimental Chemistry and you will find the same technical definition of accuracy and precision.

 

[Bfh_auto]

Funny how the internet makes everyone an expert nowadays. It amazes me how everyone on Facebook is now a Virologist. I can Google, so now I am an expert. One only has to read a few threads on any gun forum to see folks, for the most part refer to their guns and ammo as accurate. Precise is very seldom talked about. Groups of less than 1" MOA are considered accurate. Guns in general, from my life experience with them for over half a century is that they are considered accurate or not. Like the clip thing, life is too short for me to get my undies in a bundle because someone thinks they are the self appointed Grammar Nazi for today. If you want to bicker over the small stuff and talk down to other wise responsible gun owners.....so be it. Not my priority.

My thoughts are that I was taught that at least 3 different times in highschool. I'm sure t everyone else was also. If they cared. They would get it right.
I'm trying to use the motto of if you can fix it. Fix it. If you can't. Don't worry about it.

 

[trapperjohn]

in science and engineering accuracy describes how close to the true value an instrument reads while precision describes how close together each measurement is. by that definition a rifle that shoots tight groups is "precise". When I teach upper level lab classes I use targets to demonstrate the difference. Bullet holes close together but away from the bullseye are "precise but not accurate". Bullet holes that center around the bullseye but are not close to each other are "precise but not accurate" etc....
that being said. when I am talking to shooters and not dealing with engineering students I describe as accurate a rifle that shoots tight groups, just like virtually every other person who is a shooter. in all of my years in shooting I have never heard of anyone describing a rifle as being "precise" I have never seen a course or book in making a rifle precise, while there abounds books and courses in accurizing a rifle.

context of words matter. we are talking about firearms, not measurement instruments.

 

[DR505]

Accuracy v. Precision is discussed in this month’s Guns & Ammo magazine.

 

[mcb]

in science and engineering accuracy describes how close to the true value an instrument reads while precision describes how close together each measurement is. by that definition a rifle that shoots tight groups is "precise". When I teach upper level lab classes I use targets to demonstrate the difference. Bullet holes close together but away from the bullseye are "precise but not accurate". Bullet holes that center around the bullseye but are not close to each other are "precise but not accurate" etc....
that being said. when I am talking to shooters and not dealing with engineering students I describe as accurate a rifle that shoots tight groups, just like virtually every other person who is a shooter. in all of my years in shooting I have never heard of anyone describing a rifle as being "precise" I have never seen a course or book in making a rifle precise, while there abounds books and courses in accurizing a rifle.

context of words matter. we are talking about firearms, not measurement instruments.

Come now, one of the leading experts in Ballistics uses both terms in the title of one of his books.

https://www.amazon.com/Accuracy-Precision-Long-Range-Shooting/dp/B009G41VMM

I have several books on ballistics (including the above one) and when they get down into the details they use those two terms (accuracy and precision) the same way the rest of the technical/scientific world does. Yes the average shooter may play fast and loose with the terms and you can be average if you like. But if you're going to get serious about shooting, measuring the results, and trying to improve them the technical definitions of those terms have meaning and it would be good to understand and use them correctly in your studies.

 

[jmorris]

Easiest one to answer all week.

ac·cu·ra·cy
/ˈakyərəsē/
noun

1. the quality or state of being correct or precise.

pre·ci·sion
/prəˈsiZHən/

noun

1. the quality, condition, or fact of being exact and accurate.
   
   

 

[mcb]

Easiest one to answer all week.

ac·cu·ra·cy
/ˈakyərəsē/
noun

1. the quality or state of being correct or precise.

pre·ci·sion
/prəˈsiZHən/

noun

1. the quality, condition, or fact of being exact and accurate.