I’ve seen it before and let it go, but today I ran into several variations of, “Once you get the sights adjusted, this gun is very accurate” in different places on gun forums and product reviews.
Serious shooters should know the problem with that assertion, but not all shooters know it. These were shooters making the assertion after all.
Accuracy and sight adjustment (or zero) are not the same thing.
(Joe uses the term “sight angle” or “indicated sight angle” which makes more sense when you think about, which of course he has)
Accuracy is the ability of the firearm system (the gun itself, the ammo and the sighting system) to place shots consistently. The sights could be “off” considerably (bullets impacting far from the point of aim) and that gun is just as accurate as if it were putting your bullets exactly at the point of aim.
The difference is in sight adjustment, but that in itself has nothing to do with accuracy. Accuracy = consistency.
It has been said that “Sometimes the first duty of intelligent men is the restatement of the obvious.” — George Orwell (Thank You, Walter Williams, for pointing that out)
You intelligent men have your assignment, then. Carry on.
Unfortunately, it is you who are wrong in this. Precision is how tightly the group is, accuracy is how close you are to where you are shooting. if you have a 1″ group at 500 yards that is 13″ high and 30″ to the left of the target, you are quite precise, but not accurate.
As with the first commenter, Guns are precision instruments that must be zeroed to be accurate. Think of a scale which must be tared to take an accurate measurement (one that reflects the true mass of the object). Without proper tare, one would hope that the scale is a precision instrument and would give the same value for the same object.
See this:
http://honolulu.hawaii.edu/distance/sci122/SciLab/L5/accprec.html
Count me in with the first two commenters. You defined precision (or at least an element of it), not accuracy.
In the gun vernacular, “Accurizing” and all the rest refers to modifications designed to improve the ability of the system to produce tight groups.
When we say that a rifle is accurate or inaccurate, then, we’re only talking about the scope settings or the sight adjustments? When I read a review that’s talking about the accuracy of this or that rifle, we’re only discussing sight adjustments? It has nothing to do with the ability of the system to place rounds consistently to the same spot?
If that is the case, and I’m willing to accept that as a possibility, then approximately 99% of gun writers and the rest have it wrong. What we should be saying are things like, “This rifle is extremely accurate (group centers on point of aim) but it’s precision is terrible” or, “I did an accurizing job on my rifle the other day by turning the elevation adjustment three clicks down.”
So I don’t have my groups precisely centered on point of aim, regardless of accuracy? I have my groups accurately centered on the point of aim, regardless of precision.
Any engineers care to chime in here?
Encarta defines accuracy, in this sense, as; “ability to avoid errors”
Sounds a lot like “the ability to avoid flyers” to me.
They define precision as, “relating to exactness or accuracy” which would make the two words somewhat interchangeable, unless they too have it wrong.
Lets cut to the chase, and this is the point of the OP; whether we use “accuracy” or “precision” to describe a gun’s inherent ability to place rounds consistently to the same location downrange, it certainly has nothing to do with a particular sight adjustment. Sight adjustment can be changed on a regular basis by the user, so that’s not what we pay for when we spend thousands of extra dollars on an “accurized” system, and it’s not what we care about when we’re reading product reviews.
We’ve been using accurate wrong for years (engineer here). We use it when we mean precision, we use it when we mean a combination of the two.
the correct term for how well the rifle groups is precision. the correct term for how close the mean of the group is to where it is supposed to be is accuracy. same thing in measurement, you can think of it as Random vs Systematic error. you have the precision of the instrument (random variability) and the constant offset from target (which may or may not actually be constant).
so here we have an opportunity due to a fellow complaining about how some folks use accuracy in the manner in which it is actually defined (although I highly doubt that is intentional, I tend to think they mean some combination of accuracy and precision) to do exactly as asked by the poster… set the record straight on accuracy versus precision.
http://honolulu.hawaii.edu/distance/sci122/SciLab/L5/accprec.html
Not that it makes a hill of beans of difference, since everyone will continue using it wrong anyways…