Sometimes, I make careless mistakes, and a big one I made was buying the wrong scope rings.
I didn’t realize it until I started mounting one of my scopes.
If you’ve been in my shoes and don’t want to repeat the same mistake, this article is for you!
I’ll cover everything in detail, and I even have some tidbits about how to measure scope height. Some of them are even followed by law enforcement agencies!
Contents
Tools to Help You Determine Your Scope Ring Height
Here’s a list of useful tools I use to help me measure scope height and adjusting them as necessary:
- Calipers: Arguably the best way of getting an accurate measurement for firearm-related work (like the distance between your scope and receiver).
- Ruler: Results in a rougher-quality estimate. You’ll have to rely on your eyes and holding the ruler level.
- Gun Vise: This keeps your rifle secure. It also has spaces that allow you to set your screws and other parts aside.
- Torque Wrench: This lets you tighten down everything according to the manufacturer’s specifications.
- Crosshair Level: This, in combination with your gun vise, ensures your horizontal crosshairs are level.
- Boresight and Targets: These should help you zero in your scope.
How to Measure & Determine Scope Ring Height
Here are the most common ways manufacturers measure and determine scope ring height.
Determining scope ring height involves a bit of math, but don’t worry — they’re simple enough.
1. Measuring From Base to Ring Center
To give you a look at the equation, it’s:
(Diameter + 2-4 mm) / 2 = Center Height
I”ll break this approach down into three simple steps:
- Measure your objective lens diameter, which should be measured in millimeters. You can also look at the second number in your scope’s designation (The 40 in 3-9x40mm).
- Your next step is to add 2 to 4mm. This accounts for the thickness of the scope body. You can also get the exact measurement from the manufacturer.
- Divide your result by half. That number should be dead center!
2. Measuring From Base to Ring Edge
As for this method, just do the following:
- Get the measurement of your scope tube and divide it by 2. The tube is typically 1 inch or 30 mm. 1 inch is equal to 25.4mm, half of which is 12.7mm.
- Add the manufacturer’s scope ring height.
- To account for your objective lens, just divide its measurement by 2.
- Don’t forget to make sure that the result is smaller than your scope height to not hit the barrel.
The Importance of Proper Scope Ring Height
I’ll briefly walk you through some key reasons why you MUST measure scope height.
#1 It Affects Your Accuracy
In my experience, having your scope too high or too low either forces me to shoot in an awkward position or puts pressure on my scope.
This makes landing accurate shots more difficult!
#2 You’ll Avoid Damaging Your Scope and Hindering Your Rifle Bolt
The right height of your scope ring places less pressure on your scope. This will lessen its tendency to suffer any damage.
When using a bolt-action rifle, having your scope mounted too low can interfere with bolt clearance!
#3 You Can Avoid Issues With Parallax
Improper scope ring height can lead to issues with parallax.
This creates a black halo or “ghosting” effect around your lens, which results in difficult target acquisition!
#4 It Can Affect Ballistics App Calculations
Calculating for ballistics is a hassle, so I’ll take any help I can get; that includes getting the right scope ring height.
Knowing the right height for your scope rings will especially help with precision and long-range shooting.
Serious ballistics apps use it for their calculations!
Common Issues With Scope Ring Height
Mounting your rifle optics should be pretty straightforward.
In a gun shop, properly measuring scope height can be done through observation, familiarity, trial and error.
When I was still inexperienced, I had to buy multiple rings, test them, and return what remains.
Simply put, it’s costly and time-consuming.
To avoid that, I’ll talk about some issues when you try to determine scope ring height correctly.
1. Using Old Scope Rings
I used to think it was a mistake just for the sake of using old classics or saving money to use old scope rings.
However, buying new scope rings for your rifle scopes is the way to go.
This will also benefit you more over the long-term, since getting brand new accessories means NO wear and tear and having all the appropriately-sized screws.