What Do Scope Numbers Mean? (Explained)

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At first glance, scope numbers may seem like a mystery, but they’re actually not as difficult to understand as you might think. Here is everything you need to know about scope numbers, including what they mean and how they affect what scope is the right one for you.

What do the numbers on a rifle scope mean?

There are multiple lenses on a scope. The one closest to your eye that you actually look through is the ocular lens, and the lens at the opposite end is the objective lens.

For a fixed scope, the first number is the fixed magnification power, and the second number is the size of the diameter of the objective lens in mm. If the numbers on the scope are 4×32, it has a magnification power of 4, and the objective lens is 32mm in diameter.

If you’re looking at a variable magnification scope, you’ll see three numbers. The first two numbers are the range of the magnification, from low to high, and the third number is the size of the objective lens in mm. So, for example, you might see 3-9×40, which means the magnification ranges between 3 and 9, and the objective lens diameter is 40mm.

What is scope magnification?

The magnification number tells you how powerful the scope is when compared to the human eye. For example, a power of 4 means that what you see through the scope appears 4 times larger than it does with the naked eye.

So, the higher the magnification, the closer objects will appear when you look through the scope. You might think that you always want to get the highest and best magnification possible, but this isn’t always the case. It depends on what your primary use of the scope is.

Fixed Power vs Variable Power Scopes

Fixed Power Scopes

A fixed power scope has a specific magnification power that you can’t change or add to. These scopes are more reliable than variable scopes, and the image you see is brighter and sharper, so it’s easier to make a precise and accurate shot.

Because the settings are done for you, fixed power scopes are easy to use, and they’re sturdier, meaning they are likely to last longer. These scopes are also less expensive, so they’re a better choice for anyone on a budget. They have a wider view, too, which is ideal if you’re watching multiple moving targets.

Fixed power scopes have some downsides, too. If you’re shooting at shorter distances, the magnification power may be too high for the type of hunting you’re doing, making it more difficult to get an accurate shot.

Variable Power Scopes

As the name suggests, variable scopes have an adjustable magnification range, so you can get closer or move farther away, depending on the situation. These scopes are a better option for experienced hunters because you can adjust them depending on many things, like what you’re shooting, how close your target is, and where you are.

The trade-off is that variable scopes don’t have the same clarity as fixed power scopes. It can be difficult to control the magnification, especially if your target keeps moving, and you have to make frequent adjustments.

Variable power scopes are also more expensive, but they’re a better option if you’re hunting large animals in a smaller area and you don’t need the benefit of a wide view. That said, if you don’t do well under pressure, you may have a difficult time making the necessary adjustments when it counts.

Overall, both fixed and variable power scopes serve a purpose. Which one is best for you is purely down to which one you like better and how you plan to use it.

What is a good magnification for a rifle scope?

There’s no right answer to this question because a good magnification for a rifle scope depends on how you’re using the rifle.

For example, if you’re hunting varmint or deer at mid-range, something with relatively low magnification should be fine, anything from 2.5 to 4. On the other hand, if you’re big game hunting from a farther distance, go with something higher. Depending on where you are and what you’re hunting, you can find scopes with very high magnification. To my knowledge and at this time, the highest magnification I know of is on the March X-Series rifle scope with a whopping 80x magnification.

How do you read scope numbers?

On most scopes, you will see two numbers with an x in between them.

The first scope number is the magnification. If you’re looking at a variable scope, you’ll see a number range, which tells you the lowest and highest magnification you can get from the scope.

The second number is the diameter in mm of the objective lens, the front lens on the scope. What does this number tell you? The higher the number, the larger the diameter, and the more light can pass through the scope. More light makes the target looks brighter and easier to spot, especially with a good lens coating. If you’re hunting in low light, you need a large objective lens that will let in as much light as possible.

Examples of numbers you’ll find on variable power scopes:

What do the numbers 3 9×40 mean on a scope?

These numbers would appear on a variable range scope. Those before the x tell you the scope’s magnification range, so a scope with these numbers could magnify between 3 and 9 times. The 40 is the diameter of the front or objective lens in mm.

What does 4 12×50 mean on a scope?

This set of numbers would also appear on a variable scope, indicating a magnification range of 4 to 12 and a 50mm objective lens.

What does 6 24×50 mean on a scope?

You would find these numbers on a variable power scope to indicate that it has a magnification range of 6 to 24 and a 50mm objective lens.

Is a bigger objective lens better?

Remember, the size of the objective lens determines the amount of light that gets in. The more light that gets in, the brighter the image you see through the scope.

Whether or not a bigger objective lens is better is difficult to say because it depends on many factors. Some people prefer a brighter image when looking through the scope, but this isn’t always necessary. Too much light can affect other factors, like clarity. One thing is for sure, though. If you’re hunting in low light, the bigger the objective lens, the better.

Is a 50mm scope better than a 40mm?

Generally, 50mm scopes and higher are considered long-range and a 40mm is more mid-range. So, it’s difficult to say which is better because it depends on your needs. But, there are some definite differences between the two.

A 40mm scope is smaller, so it has a low-profile mount and can be more comfortable to use. These scopes are lightweight and compact, but the range shortens pretty fast. They don’t let in as much light, either. You may have some trouble that you wouldn’t have with a 50mm if you’re hunting at dusk or dawn.

That said, a 50mm scope gives you a better image in low light conditions and a little wider field of view. These are great features that many hunters love. But, remember that larger scopes are generally heavier and bulkier. They are also mounted higher. Smaller hunters may find them a little difficult to use.

Another factor to consider is the quality of the scope, particularly the glass. A 40mm scope with high-quality glass will give you a clearer image than a 50mm scope with cheap glass. So, it’s hard to say which is better between the two since there are so many factors involved.

Check out our Buyers Guide for the Best Rifle Scopes of all types!

What distance is a 10x scope good for?

A 10x scope is best-suited for about 500 yards. You can use it for distances as far as 1,000 yards, but it won’t be as accurate. It’s also worth noting that a 10x scope isn’t very useful at anything closer than 250 yards. At that point, your target is too close for the scope to be effective. So, you can see how much where and what you’re shooting affect how suitable a scope is.

What is scope field of view mean?

The field of view or FOV is what you can see through the scope from left to right when looking out 100 yards into the distance.

The field of view is related to magnification. As the magnification increases, the field of view decreases. For example, if you’re using a scope with a magnification of 6x, you can probably see everything around the target. If you increase the magnification to 24x in this same scenario, you will see less of the surrounding area, if any at all, and a more precise area of the target.

FOV is always measured at 100 yards, meaning what you see when you’re looking through the scope and focusing on something 100 yards away.

How wide should your field of view be? It depends on what you’re shooting at. If you’re hunting or shooting from 50 to 150 yards away, you want a wider field of view. This way, you can get a better idea of where the target is and where you’re aiming. If you’re hunting at a far range, a narrower field of view is better since you’re looking farther away. 

What is scope eye relief?

Simply put, scope eye relief is the distance between your eyes and the ocular lens (the one you look through). Adjusting your scope eye relief is key to preventing eye strain and ensuring you have the clearest image possible when you look through the scope.

Scope eye relief relates to magnification. If your scope has a high magnification, your eye relief should be shorter because your range is shorter. Conversely, if you have a scope with low magnification, your eye relief should be longer.

Scopes have various distances of eye relief, specifically, short, standard, and long.

Many people think short eye relief of less than 13mm is inadequate. It may seem like your field of view is fine, but you’ll find yourself constantly moving closer to the scope to see adequately. Short eye relief is particularly bad for people who wear glasses.

Standard eye relief ranges between 13mm and about 4 inches. This distance gives you a good field of view while maintaining a decent amount of magnification. These scopes are versatile, and you get a clear, crisp view.

You also have to take into consideration what gun you are mounting the scope on and the amount of recoil you have. You obviously want enough eye relief to avoid having the scope punishing your face. They don’t call it “scope eye” for nothing!

A lot of hunters prefer long eye relief scopes of at least 4 inches. This type is also the best for people who wear glasses because it gives you the most space between your glasses and the scope. Long eye relief scopes allow a little bit of movement without completely disrupting your view. They are a good option for beginners or rifles with significant recoil as well.

That said, you can lose a little bit of the light since your eye is pretty far away from the lens. This might be an issue when hunting in low light and just something to take into consideration as well.

Recommended Article: How To Choose A Rifle Scope For Deer Hunting

What is the tube diameter on a scope?

To understand tube diameter, it helps to first know a little bit about something called the exit pupil. If you hold your scope about a foot away from your face and look into the optical lens, the bright circle you see in the center of the lens is the exit pupil.

Remember, light passing through the scope is important for what you see. So, the larger the exit pupil, the more light that passes through and gets to your eye. Scopes with larger tube diameters have larger exit pupils and let more light through, but that’s not the only thing to consider when choosing a tube diameter.

Scope tubes come in a few diameters. One-inch scope tubes are the most common. They are lightweight and have a small adjustment range. There are many options available in this size, and most can mount on a 30mm scope ring, making them very versatile.

A 30mm tube is the European version of a one-inch scope. It has a better adjustment range but has the same size lens, making a 30mm slightly better for longer ranges. This size is slightly more expensive than a one-inch scope.

A 34mm tube diameter is also available. These scopes are larger and more robust than the other options, making them more durable. They’re good for precision at long distances. But, larger scopes are also heavier, which may be an issue, and they often cost a little more. Plus, they’re not as popular. It might be more difficult to find mounting accessories and rings.

There’s no right or wrong option when choosing a tube diameter. It all depends on what you prefer and where and what you’re hunting.

Length & Weight Numbers (Do they matter?)

The length and weight of the scope matter in that both affect how well you can aim and shoot. There’s no right or wrong length or width. What is more important is that you pick something comfortable to use and carry around all day if you’re hunting. If you pick a scope that’s too long or too heavy, you’ll probably have a difficult time getting comfortable using it.

What is a good weight for a rifle scope?

A good weight for a rifle scope is something lightweight enough not to hinder your movements but heavy enough to give you what you need. For example, if you want a scope that’s good for long-range shooting and is drawn to a 34mm tube, expect it to be heavier than a smaller 30mm tube.

For example, a scope with a 1-inch tube and a large objective lens might weigh 23 ounces while a 34mm scope could weigh as much as 48 ounces. But weight only matters if it matters to you. If you’re on a long hunting trip and are covering a lot of ground, every ounce counts, and you may want to go with something lighter.

Final Thought

While the numbers on a scope might seem complicated at first glance, they’re pretty easy to understand once you break them down. Take the time to think about where and how you’ll use your scope, so you can be sure to choose the right one for your needs.