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Scope Tube Sizes: What’s The Most Common [Yes It Matters]

Dakota Potts | Updated July 24, 2023 | Why You Should Trust Us | How We Earn Money
Scope tube sizes cover photo with a sig sauer scope tube

Choosing the right scope requires you to look at many different factors, but how important are scope tube sizes? What do they affect?

In this article, I’ll be diving into its importance and the most common options available so you can be sure you’re choosing the right one for your shooting purposes.

For more on optics, see our guide to the best muzzleloader scopes.

Key Takeaways

  • Scope tube sizes vary, with 1″, 30mm and 34mm being popular options
  • Each size offers its own set of advantages and disadvantages
  • Finding the right balance between functionality and personal preferences is crucial for selecting the ideal scope tube size

Common Tube Scope Sizes

Three different scopes of different sizes on a wooden table

When it comes to rifle scopes, there are primarily three popular main tube sizes: 1 inch, 30mm, and 34mm. These sizes determine the diameter of the scope tube, which houses the optics and adjustment turrets.

The 1-inch tube is commonly found on average hunting rifle scopes. They’re lightweight and offer a good balance of features for many different hunting applications.

30mm tubes offer a wider adjustment range for windage and elevation, making them ideal for long-range shooting and tactical use.

Meanwhile, 34mm tubes provide more robustness, increased adjustment, and better light transmission. They’re often used on high-end tactical and long-range hunting scopes.

So, there is no one-size-fits-all rule for selecting the ideal scope tube size. Each option offers unique advantages and disadvantages in terms of weight, adjustment range, and light transmission.

When it comes to weight, larger tube sizes may add more heft, but the choice of materials and features can mitigate this. And note that selecting the proper ring height and size is crucial for compatibility with the scope’s tube diameter.

Brown vortex scope mounted on a grey rifle

1 vs 30mm Scope Tube

The two most popular sizes for scope tubes are 1 inch and 30mm. The difference between them might seem small, but it matters to many shooters. 

Now, the 1-inch scope, as you’d guess, has a 1-inch tube. Same goes for the 30mm. People usually opt for 30mm because of its added durability and increased windage and elevation adjustments. 

However, it’s essential to know that a bigger tube doesn’t necessarily let in more light. The objective size and eyepiece size don’t change with the tube size.

Here’s a common question: will a 30mm scope fit 1 inch rings? 

And the answer is no, they aren’t interchangeable. You need to choose rings that correspond to the scope tube size to ensure a proper fit.

Four different scope ring sizes on a wooden table

While 1-inch scopes suffice for most shooters, a 30mm scope provides extra adjustment for challenging conditions or when more adjustment capabilities are needed.

But tube size doesn’t determine scope performance. Instead, it relies heavily on lens quality and build.

To wrap it up, choosing between a 1-inch and 30mm scope tube comes down to personal preference, shooting conditions, and adjustment needs. Ensure you match the scope with the correct ring size for a secure fit.

25mm vs 30mm Scope Tube

A hand holding a leupold scope

If you’ve ever heard of 25mm scope tubes being compared to 30mm, know that 25mm refers to 1-inch tubes. A 25mm scope tube has a diameter of 25.4mm, while a 30mm scope tube features a diameter of exactly 30mm.

This difference doesn’t have much effect on the scope’s capabilities other than the 30mm tube tends to offer a better adjustment range. So, choosing between 25mm and 30mm often depends on personal preference and rifle compatibility.

Here’s a quick comparison:

  • 25mm (1-inch) Scope Tubes:
    • Diameter: 25.4mm
    • Commonly used
    • Sufficient for most hunting and shooting purposes
  • 30mm Scope Tubes:
    • Diameter: 30mm
    • Better adjustment range
    • Typically preferred for long-range shooting

However, if you’ve previously heard of a “30mm vs 50mm scope” comparison, know that it isn’t referring to scope tubes but rather the objective lens size. 50mm scope tubes don’t exist. 

But the size of the objective lens does affect the height your scope rings need to have, so keep that in mind.

Close-up of a rifle scope objective lens

For more reading see our guide on how to measure sight height.

FAQs

What is the most common scope tube size?

The most common scope tube sizes are 1 inch (25.4mm), 30mm, and 34mm. The 1-inch tube size is mainly used for average hunting rifle scopes, while 30mm and 34mm tubes are preferred for long-range shooting and specialized applications.

Is 30mm scope tube better than 1 inch?

Whether a 30mm scope tube is better than a 1 inch depends on the intended use. A 30mm scope tube typically offers a greater adjustment range for elevation and windage compared to a 1-inch tube. This can be useful for long-range shooting, but for most hunters, a 1-inch tube is sufficient.

Does tube size matter in rifle scope?

Tube size does matter in some aspects of a rifle scope. The main tube diameter affects the adjustment range and turret design of the scope. However, it does not directly impact light transmission, which is determined by the quality of lenses and lens coatings.

What does a bigger tube on a scope do?

A bigger tube diameter on a scope, like a 34mm tube, offers an increased adjustment range for elevation and windage, as well as a potentially more robust construction compared to smaller tubes.


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