How to level a scope

by Tom Gaylord, a.k.a. B.B. Pelletier

This report covers:

• Why does a scope need to be leveled?
• Scopes cannot be leveled.
• A leveling solution.
• Bubble levels.
• What works
• What about a collimator?
• My moment of enlightenment.

I promised this report to blog reader Genghis Jan over half a year ago. Several times, I’ve started to write it and turned away, but today I’m seeing it through.

Why level a scope?
There are 2 reasons for leveling your scope. The first is psychological. If the reticle inside the scope appears to be slanted to one side when you mount it on your gun — and I am primarily talking about rifles today, although these principals apply to scoped pistols just as well — it’s disconcerting. The second reason for leveling a scope is to ensure the vertical adjustments move the strike of the rounds vertically, and the horizontal adjustment do the same. If the scope does not appear level, the adjustments will move the rounds off to one side or the other as they move up and down. read more

Scope dope — I hope! Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

This is an ongoing series about scope questions and issues. Blog reader David Enoch asked for it originally, but many other readers have jumped in since it began. Today, I’ll talk about adjustable scope mounts.

First things first
Why do we need adjustable scope mounts? Aren’t the scopes, themselves, supposed to adjust? Yes, they are, but 2 things quickly become a problem. First, the scopes don’t adjust as far as we need them to; and second, when a scope adjusts toward its upper and right limits, it loses its precision. I will address the second problem because it’s really the principal one. read more

Scope dope — I hope! Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2

This series was started for blog reader David Enoch; but after reading the comments many of you have written, I have to think it’s for most of you. Today, we’ll look at optically centering a scope — what’s involved and why you’d want to do it.

What is optical centering?
Optical centering means adjusting the scope until the center of the crosshairs is actually in the center of the field of view. This is difficult to understand; because when you look though a scope, the crosshairs always look like they’re centered. That’s because they’re permanently fixed in the center of a tube called the erector tube. It’s this tube that gets moved when the scope knobs are adjusted. read more

Some scope fundamentals: Part 2

by B.B. Pelletier

Part 1

This is one of the most popular reports I’ve done in a long time. That may be because scopes can be very cantankerous to deal with — hard to mount, difficult to zero, always seem to shift their zero, etc. Today, I’ll address some of the problems you can have and some ways to minimize them.

Scopes should work — no?
To the non-shooter, the telescopic sight seems like a guarantee of accuracy. We’ve all seen the movies. Put the crosshairs on the target, squeeze the trigger and you can’t miss.

Then, you try it for the first time, and you notice that you can’t keep the scope’s reticle (crosshairs) steady. As long as you hold the rifle, no matter what you do, the crosshairs move. Each beat of your heart makes them jump a little. Each breath you take in can move the scope or at least tilt it. You can minimize these movements through training, but nobody can eliminate them entirely. That’s why I shoot from a rest so often. But sometimes that doesn’t work — especially with spring-piston airguns. You have to learn the artillery hold; and since that technique goes well beyond what many people think, I’ll explain it more fully here. read more