100 yard zero

Continued from previous post.

To return to 100 yards, a zero is quite possible. In "arenas" such as Tokay's, it's possible to fail to understand what makes it difficult to determine when a zero is established even when "atmospherics" (let's call it wind or air movement and, to a lesser degree changing temperatures) is as much not a factor as is possible -- such as in a test tunnel. It's not wind or air movement that can make a zero difficult to recognize. It's irregularity in trajectory not due to "atmospherics".

Below are some examples of 100 yard zeros. Some of the ten-shot groups may be better than others, but only one of the four may show a trace of "atmospherics".





The bottom line is that it's possible to zero at 100 yards. For reasons of air movement (and sometimes temperature change) the zero may move -- as it would at every shooting distance.

Ammo behaviour is another factor that often makes it difficult to recognize whether the zero is accurate. Simply put, wind aside, .22LR bullets don't always go where they ought to go. See the examples below, where no scope adjustments were made while the target page was shot. It's not always easy to see where the zero is.


 
Tokay444 said:
That's WHY you zero there.
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You may insist that there's only truly one zero, and you're right -- only insofar as it's the distance being shot.

If you "zero" at 25 and dial your elevation for further out, you are no longer zeroed at 25. You are zeroed for the elevation adjustment.

The problem is that guys in your arena can't hit what your zeroed at unless it's only 25 yards.
 
grauhanen said:
You may insist that there's only truly one zero, and you're right -- only insofar as it's the distance being shot.

If you "zero" at 25 and dial your elevation for further out, you are no longer zeroed at 25. You are zeroed for the elevation adjustment.

The problem is that guys in your arena can't hit what your zeroed at unless it's only 25 yards.
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Your gun doesn't change it's zero'd distance when you move your elevation turret off zero. That gun still has a 25 yard zero.
 
Tokay444 said:
Your gun doesn't change it's zero'd distance when you move your elevation turret off zero. That gun still has a 25 yard zero.
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Edited: to add more clarity around the two 'zeroes' notion.

I’m not sure why I’m even wading into this argument—it seems like much of the debate is really just semantics.

That said, here’s my take: atmospherics have a significant impact on a .22 LR. For example, a 2 MPH full-value wind can push a 22LR bullet about 0.05 mils at 25 yards, 0.1 mils at 50 yards and 0.22 mils at 100 yards.

Most PRS rimfire matches have zero boards set up at 50 yards. The advantage of zeroing at 50 yards is that it gives you a clearer picture of your average group size and a easier to determine Adjust to Zero (ATZ) value. I often use apps like Ballistic-X to calculate ATZ. Of course, a 50-yard zero is more sensitive to atmospheric conditions, so you need to apply some judgment when making adjustments.

A 25-yard zero, on the other hand, is less affected by atmospherics. The tradeoff is that it can be hard to spot individual bullet holes, which makes calculating ATZ more difficult.

Both distances can work well, it really depends on how windy your range is.

As for the idea of "two zeros," that’s largely dependent on your rifle setup, especially your sight height and velocity. In terms of ballistic solvers, they are agnostic to which of the 'zeroes' you put in. For my particular setup (bore height, bc and velocity) 27 and 50 yards are nearly identical elevation (my two 'zeroes), testing it in AB (inputting a 27 yard and 50 yard zero) I got the identical solution for 200 yards.

At the end of the day, your goal should be to input the most accurate zero (and supporting variables) into your ballistic solver. Both 25 and 50 yards (and anything inbetween) are viable for zeroing a .22 LR. A 100-yard zero is generally not ideal, as group sizes tend to open up, and even the slightest wind can significantly affect point of impact due to the poor ballistic coefficient of .22 LR rounds.
 
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Jahnj0584 said:
Sometimes, someone has a take that is so dumb and yet somehow so strongly held that I dont even want to engage with it.

Zero your SCOPE for 25y, I dont care. It's just practical for everyone else. Your GUN can't be zero'd for any distance.

You do you, Boo.
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No need to zero your scope if there isn’t a rifle under it. You’re zeroing the system, if you want to argue semantics.
 
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