Most shooters define minute of angle (MOA) as “an inch at 100 yards.”
MOA is a word describing the “1/60” measurement. Though MOA means “minute of angle” for the world of firearms, it means “minute of arc” on science and the academe.
If you can still recall this lesson from your basic mathematics, angles can be measured in degrees, minutes, or seconds.
A full circle consists of 360 degrees. When a degree is divided into 60 parts, each 1/60 degree is called a minute. When a minute is divided into another 60 parts, each 1/60 minute is called a second.
Precision shooters use MOA to express their need for accuracy. When you fully understand this term, it saves your time when adjusting your rifle’s scope. Aiming at the center of the target will be almost perfect regardless of your distance from the target.
Still, precision matters with your rifle and bullet’s ballistics, natural conditions, and your skills.
How MOA Affects Shooting Precision?
For shooting jargons, MOA is described as an “impact difference” of one inch at a distance of 100 yards. In a real sense, MOA is not precisely an inch at 100 yards.
Specific calculations reveal MOA’s measurement as 1.0471996 inches at 100 yards. For simplification purposes, it is rounded down to 1 inch to prevent decimal confusions.
MOA is specifically applicable when adjusting your scopes. Hitting your target might be a hard job. But such scope adjustments changes the angle of elevation of your rifle.
Assume you are 100 yards far from your target. Your first firing attempt might not critically hit your target in spite of the crosshairs aimed specifically at the center of your target.
Adjusting 1 MOA modifies the accuracy of your aim, bringing you 1-inch closer to a critical hit. Careful analysis of angles and distances will lead to lesser spent bullets and time-efficiency.
The table below gives you a quick preview of adjustments for 1 MOA.
Since MOA is fundamentally an ever-widening angle, the size of a MOA widens proportionally to the rate of distance increment.
These decimals might annoy you. But you need to reconsider the estimated 0.47-inch difference at 1000 yards. Almost at 0.5 inches, it has a significant impact for precision shooters.
Remember this concept: 1 MOA is not always an inch for all distances. Different distances give different inch adjustments for the same 1 MOA. Also, different scope products use different click adjustments needed for every MOA adjustment.
Thus, you need to consider these formulas carefully.If you want exact calculations, multiply the “inches per MOA” by 1.0471996.
- Inches per MOA = (Distance to Target in Yards) / (100)
- MOA Adjustment = (Inches of Adjustment Needed) / (Inches per MOA)
- Adjustment of Clicks on Scope = (Number of Clicks per 1 MOA on Scope) x (MOA Adjustment)
Your bullet’s flight is affected by internal and external forces. Your primer, powder type, and powder burn rate may cause significant fluctuation on your MOA calculation. Also, you need to consider the natural conditions such as wind speed, humidity, and air density.
On the first 100-yard flight, natural conditions might not affect the speed of your bullet. Thus, the adjustment is still close to 1 inch. But on a longer flight, natural conditions will slow down your bullet’s speed.
For instance, at 1000 yards, it may not even reach the 10-inch adjustment. With these in mind, you need to analyze the MOA you need to hit your target carefully.
Applying MOA to Reality
Adjusting the scope of your rifle significantly changes the angle of your barrel to the target. Your scope has two knobs: usually one on top and one on the side of the scope body.
The top knob adjusts the elevation for the up and down calibration. The side knob adjusts the windage (air resistance of your bullet) for the left and right calibration. These scopes are designed to calibrate your aim through graduated increments.
Most scopes sold in the market have a setup of ¼ MOA adjustment per click. So if you need 1 MOA adjust, you need four clicks.
While turning the knob, you will feel a stop or click since all scope knobs are designed to function that way. To aid you visually, most knobs have fine hash marks.
You need to know the setup of your scope. Some scope knobs have its click set at 1/8 MOA, ½ MOA or 1 MOA adjustment per click.
You already know those internal and external forces affecting your rifle’s accuracy. Assume you are shooting at 200 yards with your rifle at 0 MOA adjustment.
Your first group of shots accurately hits your target. But for the next shots, you notice a deviation of four inches lower from your intended aim.
You can use MOA to compensate the deviation, which is 2 MOA adjustment or 8 clicks for a scope that has ¼-MOA clicks. MOA is an effective remedy for those deviations and inaccurate targets.
MOA is the specific language of your rifle. Understanding MOA will help you throughout your precision needs. When sighting in a rifle, you need the concept of MOA.
When ranging a target at an unknown distance, you need the concept of MOA. When gauging your rifle’s accuracy, you need the concept of MOA. All sighting and precision analysis need a deep knowledge with regards to MOA.
You always have to keep those increments you get for the same MOA in mind. Also, you need to carefully analyze the impacts of the natural conditions to the precision of your rifle.
Once you master the concept of accuracy through MOA, real-world hunting will surely excite your mind. The precision analysis is always fun if you aim to be an expert precision hunter.