When To Stop Chasing A Zero?

Jul 30, 2005
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DFW, Texas
#1
What is good enough for a rifle zero? For example using a (x,y) coordinate system, I have never gotten a center group of (0,0) at 100 yards for a ten shot group. So at what point do you say it is zero'd?

For example, I recently zero'd a hog gun using 300Blackout.

A 10 shot group has a center of (-.17,.09) in inches. Converting to polar coordinate, that comes to .2 inches off center at 61 degrees. The Mean Radius is .49 inches. That seems pretty good to me for hogs.

But I am curious when others stop trying to zero and call it done.

 
Nov 5, 2013
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#2
usually when i hit 1/4" dots more often than not, i call it good...even if its slightly off and it bothers you, you can put the offset into any ballistic app to account for it

for shooting hogs with a 300blk...youre plenty close enough
 

diverdon

Online Training Member
Dec 21, 2011
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#3
If your finest adjustment is .1 mil (and this depends on your scope) then the smallest adjustment is .36 inches at 100 yards. As your maximum error is .2 inches if you adjusted even a single click you would be off .16 inches in the other direction. (and the .04 could be shooter error or environmental conditions) I would leave it if my finest adjustment was .1 mil. If my finest adjustment was 1/4 moa that is .25 at 100 yards and your data has you off by .2 so i would give it a click so it was perfect---and then I would call it perfect because I'll never shoot .05 at 100 yards.

Edited to add, shooting for hogs, I might have quit when I got within a half inch.
 
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Lowlight

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Apr 12, 2001
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#5
You can actually stop anywhere thanks to software... as long as you are hitting close enough at 100 to do the job you need too, simply determine the True Range Zero for your software and drive on

<iframe width="560" height="315" src="https://www.youtube.com/embed/kb5NOcgDozw" frameborder="0" allowfullscreen></iframe>
 
Apr 10, 2017
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#6
Good question id like to add to it, how important is it to know that whatever distance you zero at that, that this is the exact distance you have measured? For example on bryan litz video of doing the tall target test he takes a tape measure to measure the exact distance from rifle to target. Id imagine that when setting your zero you should also be this exact in determining your zero distance. how many are using 300ft tape measures to measure their zero distance?
 
Feb 14, 2017
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DC Area, MD
#7
Good question id like to add to it, how important is it to know that whatever distance you zero at that, that this is the exact distance you have measured? For example on bryan litz video of doing the tall target test he takes a tape measure to measure the exact distance from rifle to target. Id imagine that when setting your zero you should also be this exact in determining your zero distance. how many are using 300ft tape measures to measure their zero distance?
LRF, but also shooting from a known distance range should get you within feet if not inches of the known distance.
 

Lowlight

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#8
I stopped using a 300ft tape measure... the error using feet is tiny, as it is with the tape measure because pulling it tight is also not so easy across 300ft. You have to anchor it. The tape is used to test scopes, not zeros.

We changed the Terrapin LRF to feet and check the results and any error between feet and inches is so small you cannot figure them in either. So it's a wash.

Most public ranges are off yard line wise, and within that distance, you have a danger space with the fall of the bullet. It only becomes critical on the backside of the trajectory and out pretty far where the danger space falls to a handful of yards.

At 100 yards your zero is good from about 78 yards to 109 yards anyway, but you can just measure the small offset as noted in the video and correct the true zero range. Coldbore has a True Zero Range calculator in it too... but that stuff is to help eliminate errors at longer distance (backside of trajectory again) vs inside most people's useable ranges.
 
Apr 10, 2017
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#9
Thanks frank that clarify's the zero question. So in regards to the tall target test without a LRF would you still recommended a 300ft tape measure to measure exact distance when doing the tall target?
 
Jan 23, 2010
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#10
Thanks frank that clarify's the zero question. So in regards to the tall target test without a LRF would you still recommended a 300ft tape measure to measure exact distance when doing the tall target?
I do, and beleive you should as the actual distance is a factor in the equation to determine the percentage of tracking error. I'm interested in Frank's take on this as well.
 
Jul 30, 2005
121
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DFW, Texas
#11
Thanks. I shoot in my backyard, and have exact measurements marked off, so that is not an issue.

Looks like a consensus is to zero till you are inside the adjustment range of your scope.
 

Lowlight

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#12
Like I said, I found measuring the distance in feet vs using a tape in inches had no bearing on the results... it's at least 4 places past the decimal point before it changes the results

When the scopes only adjust in .25" or .36", I find it hard to worry about when the number might be .0001 off because you didn't use inches. We ran the numbers working on the Targets USA Scope testing tool and it's a wash.

Most people are making far bigger errors in ranging, public ranges with incorrect distances marked, being at the wrong end of the firing line adding or subtracting 5+ yards, so if your laser is not accurate at 100 yards, what makes you think it is working at 1287 yards, the short answer is, it is, it is working fine, the +/- is acceptable. That is why Bryan used a tape because none of his lasers agreed on the distance. So we started off by checking our laser out, knowing where that hits eliminates the need for a tape measure later.

If the tape measure is not secured and tight, you have every bit the same error as using feet from your laser. You can probably test your laser under the yard setting and know where it stands too if it does not have the yards feature like the Terrapin does.

Finally consider the size of the aiming point people use... many use a 1", 3/4" or similar size dot, there is a lot of wobble in there if you are shooting it.
 
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RAJ1986

New Hide Member
Feb 11, 2018
2
1
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#13
Good question id like to add to it, how important is it to know that whatever distance you zero at that, that this is the exact distance you have measured? For example on bryan litz video of doing the tall target test he takes a tape measure to measure the exact distance from rifle to target. Id imagine that when setting your zero you should also be this exact in determining your zero distance. how many are using 300ft tape measures to measure their zero distance?
I don't but I surveyed for a while in my life and know 300ft tape isn't always 300ft found some to be off a few feet
 
Aug 10, 2001
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Arizona, good place for me...
#14
I see a lot of ammunition, and more importantly, bore life, going up in smoke for no beneficial return.

Consider each shot, both after, and before the next. If you're not achieving anything, stop; and figure out why. Taking more shots without doing that is literally, a waste. Taking more shots will not make a problem go away.

Greg
 
Likes: Garvey
May 1, 2010
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Melissa, Texas
#15
What is good enough for a rifle zero? For example using a (x,y) coordinate system, I have never gotten a center group of (0,0) at 100 yards for a ten shot group. So at what point do you say it is zero'd?

For example, I recently zero'd a hog gun using 300Blackout.

A 10 shot group has a center of (-.17,.09) in inches. Converting to polar coordinate, that comes to .2 inches off center at 61 degrees. The Mean Radius is .49 inches. That seems pretty good to me for hogs.

But I am curious when others stop trying to zero and call it done.

A good enough zero is as tight as the ammo can shoot, and as tight as the scope can dial. If you do not KNOW how tight that ammo can shoot, shoot two or three to get an average. Then dial the average of the group to where you want your zero. So lets say your group is 1" diameter, find center of the group measuring from your desired POI to the group. Dial the group into correction.

In the case of a true 1/4 to 1/2 MOA rifle and load, then your largest error of zero may be what your scope subtends to. In the case of Mil, you may find that your zero is .05 Mil off from desired. Well, you can't dial any tighter than that, leave it alone. If your zero is a full 1/10 Mil off, and your rifle/ ammo will shoot tighter, dial that 1/10 of correction in.

And inches have no bearing on this 100 yard coversation, same as they do not have any bearing on the 1000 yard conversation. What do you see the error in, Mils or MOA? What does your scope dial in Mils or MOA? The reticle is the ruler, and the turrets speak the same language. If you are using the abomination that is Mil reticle, MOA turret, then you have to do a conversion, but you still do not have to walk down to the target with a ruler. I spot in Mil, some of my customers are using MOA. What ever I see in Mil, I convert the correction to MOA and tell them that number.

Mil X 3.43 = MOA
MOA ÷ 3.43 = Mil

The way I remember that number is 343 FDNY Firemen died on 9/11, may they rest in peace.

When I am spotting at distance, I just take what I see in Mil and multiply that by 3 and a half, in my head, and it's close enough.

A quality laser range finder is close enough to zero a rifle at 100. As Frank mentioned, 75 to 110 yards is the same zero. If your range finder has a 1-3 yard error, it doesn't matter.