Tutorial What is the turret click value on your rifle scope... REALLY?

What does a click mean on my scope?​


Our scopes come from the manufacturer with a number of different "specs." One of those specs is the turret click value. Most scopes designed for precision shooting have turret clicks that are 1/4-MOA or 1/10-MIL.

I'm an "MOA guy," for now. So, according to the manufacturer of my scope, each click of the turret is 1/4 or 0.25-MOA.

BUT IS IT REALLY???

According to what I've read, many scopes are not EXACTLY calibrated to the value in the specs. They can be off a bit. At close distances, it may not matter. For hunting at normal distances, it is probably "close enough" to get in the "vital zone." But, for precision target shooting, it can matter. At longer distances, it can matter even more.

There are various tests you can run to see if your scope is "tracking" well. One of them is the "Tall Target Test." The purpose of this test is to determine the ACTUAL turret click value of your scope. Then, when you are using a ballistic calculator to spit out a "firing solution" at a distance beyond your zero, you will get a more precise result. Make sense?

Here's a link that explains the Tall Target Test process.

Let's put it to the test at the range.​

So, I went out to the 100 yard range with the mission of determining my scope's true click value.

Basically, you just need a vertical line down the middle of a tall piece of paper. It needs to be perfectly vertical when it's stapled to the target backer. I used a plumb line to verify. Naturally, your scope needs to be level with your rifle. And, when you're shooting this test, you need to be sure that your rifle / scope is vertical.

After you've confirmed your zero.... Pick a spot near the bottom of the vertical line as your "bullseye." Shoot a group there. Then dial 20 or 30 MOA (or MIL equivalent) UP in elevation. How much... depends on how much room you have to dial up. But, the more the better. In my case, 20 MOA worked well.

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The "Tall Target Test" yielded some very interesting results. I ran the test twice. Both times, the result was EXACTLY the same... to three decimal places! Here are my calculations.

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As you can see, my Expected Point of Impact Shift (EPOIS) with 20-MOA (80 clicks) dialed would be 20.94 inches (20 MOA x 100 yards x 0.01047). But, the ACTUAL Point of Impact Shift was 19.688 inches. It was short.

The Correction Factor is what I would use if I didn't have a ballistics app that allowed me to input the actual click value. So, if a ballistics chart (that assumes true 1/4-MOA click value) told me I need to dial UP by 16 clicks (or 4-MOA) for a particular distance, I would multiply that by 1.0636 (about 6%), which would be 17 clicks of actual dialing. If the chart told me I need to dial 40 clicks (10-MOA), that would be 43 clicks of actual dialing.

But, since Strelok Pro allows me to enter in a corrected click value, and my scope's actual click value is short by 6% (6.36%, to be precise), I can just do the reciprocal of 1.0636, which is 0.235. My scope's actual elevation click value is 0.235-MOA. Done another way... 94% of 0.25 is 0.235. I hope that made sense.

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So, the cool thing about Strelok Pro (ballistic app) is that I can enter that 0.235-MOA click value into my scope's data. Now, the app will give me more precise "firing solutions."

Update....

When I originally performed this test, I assumed the range distance was as marked... 100 yards. I didn't have a tape measure that long, nor did I have a rangefinder.

Well... a friend (@BeerHunter ) and I discovered it wasn't exactly 100 yards. Rather, it was 96.28 yards. Almost 4 yards short.

It makes a difference in the calculations. A pretty big difference! So, I re-ran my numbers, using the corrected distance.

The good news is that my scope was tracking even better than I previously thought / calculated. Instead of being 6% off, it is only 2.35% off. So, instead of the corrected click-value being 0.235-MOA, it's actually 0.244-MOA.

What does that mean at 1,000 yards?​

So, if my scope is dead-on, and there's no wind, and the weather is exactly the same as my zeroing weather, and the ballistics calculator is perfect, AND I'm a perfect shooter... theoretically, the bullet will land square in the x-ring at 1,000 yards.

I punched that into Strelok with the two different turret click values for a 1,000 yard firing solution.

When set at the factory-claimed 0.25-MOA, it tells me to dial up 154 clicks. So... 154 clicks at a value of .25-MOA is 38.5-MOA. Strelok is calculating that my elevation (due to bullet drop) needs to be 38-1/2 MOA to be on target at 1,000 yards.

When Strelok accounts for the corrected 0.244-MOA click value, it increases the number of "clicks" to 158... or 4 more clicks. The total MOA is effectively the same. The correction in MOA HAS to be the same, right? The difference in the number of clicks is due to the actual click value. 38-1/2 MOA is the elevation correction for that distance, no matter what your turret click value is. The only thing a turret click value discrepancy can change is the number of "clicks." Make sense?

Four more clicks at a 0.244-MOA click value is 0.976-MOA for the 1,000 yard firing solution. Without knowing this information (my scope's true click value), the erroneous firing solution would cause me to be off (low) by about 10 inches at 1,000 yards.

On a steel target, I might still be on. But, for bullseye competition, it's the difference between an X-ring and a 10-ring impact.

That's fairly significant at that distance. Obviously, it becomes less significant at shorter distances. While I have shot as far as 1,000 yards - once. And, I've shot at 600 yards several times. I'm lucky to get 300 yards at any range reasonably close to home.

300 yards​

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600 yards​

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If I got any of this wrong, let me know!
 
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