Group size has long been the standard by which accuracy is judged and measured. A single miss or hit can be the product of luck or random chance, but a tight group is incontrovertible proof of accuracy and precision. But, not all groups are equal, even if their overall size is the same.
When we talk about group size, we generally mean the distance between the two most distant hit markers or holes, but there is a second meaning that is no less important—the number of shots that make up the group. Both of these group sizes matter, and below, we’ll explain how.
Understanding Precision Shooting
In order to talk productively about precision shooting, we first have to be on the same page regarding the standards and vocabulary of the sport.
Measuring in MOA
Firstly, it’s important to understand how groups are measured. The precise details can vary between different locales, league rules, and so on, but the most common generally accepted standard is to measure a group using the distance between the centers of the two most distant holes.
Measuring from the center of the holes is important because caliber size varies. If we measured from the outside of the target holes, a larger caliber would be slightly penalized over a smaller one, even if the accuracy of the two firearms was the same. If we measured from the innermost side of the holes, nearest to the center of the group, the inverse would be true. We measure from the center to keep things even.
You’ll also need to understand how MOA measurements work. If you’ve read our article on MIL vs MOA measurements or are familiar with the function of MOA-based reticles and rifle scope adjustments, then you probably already have a good grip on this.
If not, the short version is, MOA or minute-of-angle is a system of measurement based on fractions of an angle, which allows for a productive comparison between sizes at different ranges. 1 MOA is equal to 1.047 inches at a distance of 100 yards, often rounded to 1 inch.
Because an MOA is an angular measurement, the farther the distance, the larger a single MOA becomes. So, if we continue rounding to 1 inch, then one MOA would become 2 inches at 200 yards, 3 inches at 300, and so on.
This matters because it allows us to directly compare group sizes regardless of the distance at which they are fired. A five-inch group would be quite impressive at a thousand yards, but considerably less so at 25. A 1 MOA group, on the other hand, is respectable at any range.
Because a 1 MOA group is commonly used as a benchmark, you may occasionally hear something described as sub-MOA. This simply refers to anything capable of producing a group smaller than 1 MOA.
Accuracy Vs Precision
Accuracy is another term that gets thrown around with a variety of different meanings. Technically, accuracy is a measure of how close your shots land to your intended target, e.g., a 5-round group with a center located two inches from the bullseye would be considered more accurate than a group with a center ten inches from the target. However, the size of these groups is, essentially, irrelevant to how accurate they are.
Instead, group size is a function of precision, which in the context of marksmanship is a measure of how consistent your rifle is in delivering rounds to the same place shot after shot. Of course, user, ammunition, and environmental factors all play a role, so a large group doesn’t necessarily mean a rifle is imprecise. Nevertheless, the size of the group is a function of precision—regardless of how close that group is to the target.
As such, it is possible to have a very precise, very inaccurate group if your shots land in a very tight cluster, but nowhere near the intended target, or a very accurate but imprecise group if your shots land very far apart from each other, but with the center of the group directly over the bullseye.
Unfortunately, when it comes to marksmanship, accuracy tends to get used colloquially to mean both accuracy and precision. The two get conflated because when it comes to practical ballistic applications, one is useless without the other.
At the end of the day, both accuracy and precision are required to be able to reliably hit the target when it counts, whether you’re firing at a steel silhouette or a prize stag. A large group that’s roughly where you want it won’t ensure an ethical shot on a deer, nor will a tiny, half-moa group that’s nowhere near the animal’s vitals.
Round Count (And Why It Matters)
The most surefire way to get a tiny group is to fire a single shot. In so doing, you’re guaranteed a sub-moa group—but you also shouldn’t be surprised if no one is very impressed.
That’s because a single shot doesn’t really tell you anything about the performance of the rifle or user. To gather useful information, you need a larger sample size. This same principle holds true with multi-round groups.
The more rounds you fire at a single target, the higher the quality of the information you gather about the accuracy and precision of your setup. It’s simple statistics, really—a larger sample size yields a more reliable conclusion.
This is because the more shots you fire, the less random chance affects the group. Higher round counts allow the little deviations that affect each shot to cancel each other out, leaving an end result that’s both accurately descriptive of the rifle’s performance and predictive of what you can expect going forward.
The industry standard for accuracy testing is often considered to be a three-round group. That’s usually the metric used for factory accuracy testing, and typically the round count specified when manufacturers give an accuracy or precision guarantee.
A three-round group is a whole lot better than a one-round group, but it still leaves something to be desired. Many rifles, if fired enough times, can eventually print a sub-moa three-round group, even if only by random chance. It’s not uncommon for a rifle that is capable of producing an MOA 3-round group to also produce a 2- or 3-MOA group, even with the same ammo, user, and atmospheric conditions.
Up that round count to 5 or 10, though, and you’ll see your group sizes homogenize very quickly. The larger round count helps to even out all the random little factors that cause minor deviations in your shots, resulting in a group that’s much more indicative of a particular rifle and user’s capability.
But, larger round counts also eliminate the ability to cherrypick good groups as proof of performance, and so moving from a 3-round group (with the sub-par groups discarded as “fliers” or “outliers”) to a 10-round group often turns a 1-MOA rifle into a 2- or 3-MOA one.
Improving Your Groups
Now that you understand how groups are analyzed and how we use them to measure performance, it’s worth considering how they can be improved.
There is a nearly infinite variety of ways in which accuracy and precision can be improved, so we can’t cover them all, but here are some of the quickest ways to shrink your group size.
Upgrade Your Optics
If you’re still using iron sights, upgrading to a red dot or magnified optic is a nearly surefire way to shrink your group size. The benefits of magnification are largely self-evident, but we go in-depth on the value of red dots in our article on iron sights vs red dots.
In any case, upgrading from iron sights to a dot, or from a red dot to a scope, is all but guaranteed to improve your groups. These optics each allow for an easier and more precise sight picture than the last, which tends to translate into greater practical accuracy. If you’re unfamiliar with the difference between mechanical and practical accuracy, we recommend checking out our article on the topic.
Correcting Errors
Few (if any) among us fire our rifles perfectly. Correcting even minor errors in marksmanship best practices can have a significant effect on performance, whether that means cleaning up your trigger press, improving your positioning, or working on more advanced techniques like breath control.
Alternatively, it’s not uncommon for even seasoned marksmen to find that they have been using their optics improperly or imperfectly. Properly adjusting your diopter to your eye, correcting any parallax error that may be present, and learning to use your reticle to its fullest potential can all have a significant impact on practical accuracy.
Improving Equipment
While we generally find that it’s easiest and most impactful to work on improving the user, rather than the tool, if you’re already using your rifle to its fullest mechanical potential, then upgrading is the obvious solution.
This doesn’t have to mean a new rifle. Modifications like an upgraded barrel, improved stock, or match-grade trigger can all have a noticeable effect on accuracy.
If you’re interested in accurizing your existing rifle, you can start by reading our guide to the top 5 accuracy upgrades for your AR-15.
Conclusion
Group size is an important metric for any marksman because it is the best method we have of testing the accuracy and precision of a particular rifle, user, and setup. It provides a baseline for performance and lets the user know their limits so that they can accurately estimate their abilities going forward—a crucial capability for hunters, competitors, or anyone who uses a firearm for a more serious pursuit than mere recreation.
While a 3-round group can be a reasonable indicator of performance, a higher number of rounds provides a greater sample size, and therefore, a more accurate picture of capability. Any marksman who wants to know their true potential should consider moving up to 5- or 10-round groups.
