In a set of measurements, accuracy is closeness of the measurements to a specific value, while precision is the closeness of the measurements to each other.
Accuracy has two definitions:

More commonly, it is a description of systematic errors, a measure of statistical bias; low accuracy causes a difference between a result and a "true" value. ISO calls this trueness.
Alternatively, ISO defines accuracy as describing a combination of both types of observational error above (random and systematic), so high accuracy requires both high precision and high trueness.Precision is a description of random errors, a measure of statistical variability.
In simpler terms, given a set of data points from repeated measurements of the same quantity, the set can be said to be accurate if their average is close to the true value of the quantity being measured, while the set can be said to be precise if the values are close to each other. In the first, more common definition of "accuracy" above, the two concepts are independent of each other, so a particular set of data can be said to be either accurate, or precise, or both, or neither.

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  1. rangerstx4

    M82A1 accuracy testing

    Recently got my hands on a new production M82A1 Barrett. After reading through many forums I see a lot of “knowledge individuals” talking about how inaccurate the rifle is. One even mentioned it couldn’t hit a barn from inside a barn. The last couple weeks I’ve done some testing and here are...
  2. L

    interview questions for sonoran desert institute assignment

    I am currently attending Sonoran desert institute, and one of my assignments is to interview a subject matter exert in regards to ballistics and rifle accuracy. I need someone who can explain trajectory, wind drift, recoil, velocity, and accuracy. And give two examples on you running through the...
  3. D

    Recommend an accurate, reliable handgun I can add a rail to?

    I'm a little bummed out. Got a call from my gunsmith. He said he was not recommending adding the rail to my S&W 19-3 revolver. Now I'm thinking about selling it and getting another handgun. I love my 19-3 because it is a revolver and therefore shoots reliably. And because it's fairly accurate...
  4. RaceFan

    OLD Marlin 60 & Accuracy Issue

    My Marlin 60 was the very first firearm given to me; so ~40 years old now. Until a few months ago, it sat unfired for more than 25 years. After a thorough cleaning and lube job, I fired it and tested several ammo types. The bullets flew everywhere. At 50 yards, I would get one hit near target...
  5. Phred

    30 Rounds Of .223 Reloads For An Accuracy Test

    I would like an experienced shooter to test these and compare them to your current load. Even though I shoot off a bi-pod, I am on heart meds and they cause my hands to shake a bit. So I really need some one with steady hands to evaluate these. A chrono would be a plus, but not required. I have...
  6. RaceFan

    Improved Accuracy with Laser

    I have never used a laser on a pistol until a recent purchase: P938 9mm with an integrated CT red laser. I LOVE IT. A couple of flyers as I was getting used to the 1911-style trigger. The pistol didn't seem to care whether I used 115gr or 147gr. Target at 21 feet. I didn't have a tiny torx screw...
  7. D

    Time to redefine accuracy...Mini 14 surprise

    So was at the range with my Mini 14 again yesterday. Hooked up with a shooting buddy, and one of the targets he brought along was a 12" steel gong that he set at the 300 yard line. I was playing around with my Mini at the 50 yard line, while he was banging away with his 7mm-08 on the gong...
  8. G8rHunter

    New Rifle Barrel Break-in for Accuracy?

    How to Break-In a Rifle Barrel How to break-in a new rifle barrel BGFTRST: Seasoning Your New Rifle : Cabela's The Dirty Little Secret of Gun Cleaning Okay, I know many disagree but here's the articles I read from reputable sources. The last article is by a Cabela gunsmith.
  9. surevaliance

    Reliability and accuracy of Ruger Mark IV 22/45 Lite?

    I was dreaming about new plinker Kel-Tec CP33, but it seems like the pistol will be outlawed in WA before distributors get it. Therefore, I am considering Ruger Mark IV 22/45 Lite. Will appreciate all opinions regarding its reliability and accuracy.
  10. arakboss

    MOA Accuracy vs Investment to Get There

    How do you decide what accuracy is worth cost wise in a particular rifle? For example if you purchase a budget hunting rifle and it achieves 1 MOA out of the box with an ammo it likes, how do you decide how much to spend to cut that down to 1/2 MOA, 1/4 MOA or even one ragged hole?
  11. rangerstx4

    CZ Scorpion Evo Accuracy Testing

    Working on trying to find the best round for the CZ Scorpion Evo S1. I tested 6 different self defense rounds. I used a brand new Evo w brace. Mounted a Bausch and Lomb using a Bsquare mount. Then sat it in a cradle on a bench. 5 shot group results below at 50yds Hornady 147gr XTP 3.5in group...
  12. Pierre

    Finding that "one hole" accuracy.

    It was mid-may when I set up to shoot a 200 yard target at the range out back of the place. By the time I was ready at noon the temperature was a mild 75 degrees. I rode the Rhino downrange and stapled a solitary target to the frameworks. Dead center was a black one inch paster. My shooting...
  13. Alan12013

    Upgrading from synthetic stock

    Has anyone changed from a standard synthetic to a chassis system or better yet, a nice wooden varmint or bench rest stock and compared their bench rest shot groups before and after? I've got a new Bergara B-14 hunter and installed a cheapo 20 dollar "vlife" bi-pod on it. Today I noticed that...
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