Parallax adjustment/ "head bop" question.

Parallax adjustment/ "head bop" question.

Joined: July 24th, 2010, 1:44 am

January 3rd, 2011, 9:47 pm #1

I've always done my scope parallax adjustments at my zero distance (30 yards normally). I'm wondering if it's better to do the "head bop test" at closer or longer distance, or doesn't it matter.

The reason I ask is that I'd like to do my scope setup upstairs in comfort, but I can only get about 16 yards of distance.

Thanks in advance for any info how y'all "big dogs" do it!
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Joined: May 14th, 2004, 4:11 pm

January 3rd, 2011, 9:59 pm #2

I was always under the assumption that one uses the "head bop" at every range from 10-55 or whatever ranges you set the scope for. That said I usually only use it at the farther ranges when I am setting up a scope.

Jeff P(not a big dog)
Last edited by pad617 on January 3rd, 2011, 10:27 pm, edited 1 time in total.
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-bp
Joined: June 5th, 2009, 4:21 pm

January 3rd, 2011, 10:01 pm #3

it's the only true way to be sure your distance settings are correct. you can focus a scope 3x and get 3 different distance readings (unless you're better than i am)

(which is a possibility)

-bp

seriously, it pays to bop your head around any time you focus on a target, if the shot is important and there's time.

Last edited by -bp on January 3rd, 2011, 10:07 pm, edited 1 time in total.
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Joined: October 23rd, 2005, 9:50 pm

January 3rd, 2011, 10:08 pm #4

I've always done my scope parallax adjustments at my zero distance (30 yards normally). I'm wondering if it's better to do the "head bop test" at closer or longer distance, or doesn't it matter.

The reason I ask is that I'd like to do my scope setup upstairs in comfort, but I can only get about 16 yards of distance.

Thanks in advance for any info how y'all "big dogs" do it!
If you know your velocity. Plug in your data to "chair gun", or a similar program.

This will give you the info needed to figure out your settings.

Personally, I prefer to set my zero at about 35 -36 yards. Still have to adjust the near targets, but I have little or no need to adjust beyond. Just hold and shoot. Oh, I get a bit of flack about this, but it works for me. But then my velocity at the barrel is 875 on one and 920 on the other.




Just my humble opinion
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-bp
Joined: June 5th, 2009, 4:21 pm

January 3rd, 2011, 10:21 pm #5

my problem is i think i'm shooting something at 35 yards, so then i set my dial for 35 yards, and if i take the time to bob my head up and down, i find out i'm at 33 or 37 yards

at those distances, it doesn't make a dime's worth of difference; the holdover will be the same, but from 10yards through 20 yards, (and from 40 yards to 55 yards) it can make a huge difference. big holdover diff between 50 yards and 55 yards, for instance

my zero is usually at 10 yards and 50 yards, depending on the temp

when it's colder out, it's 10 yards and 45 yards

zeroing on 10 is probably not the best idea, but it's what i started with. confirming that same zero at the second point where the trajectory crosses the line of sight (45 or 50 yards) is much more accurate than sighting at 10y.

stay well,

-bp

Last edited by -bp on January 3rd, 2011, 10:22 pm, edited 1 time in total.
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Joined: July 24th, 2010, 1:44 am

January 3rd, 2011, 10:32 pm #6

I've always done my scope parallax adjustments at my zero distance (30 yards normally). I'm wondering if it's better to do the "head bop test" at closer or longer distance, or doesn't it matter.

The reason I ask is that I'd like to do my scope setup upstairs in comfort, but I can only get about 16 yards of distance.

Thanks in advance for any info how y'all "big dogs" do it!
I adjust my ocular so that when I do a "head bop" (move my eye side to side) the crosshairs stay welded to the kz no matter where I place my eye. I do this at 30 yards because that's my normal zero distance. I did notice that when my ocular is adjusted for "zero crosshair movement" at 30 yards the crosshair isn't perfectly crisp. If I adjust the ocular so the crosshairs are perfectly crisp then I get a bit of crosshair movement as I move my head sise to side.

What I was wondering is if a "zero crosshair movement adjustment" (made with the ocular) at 30 yards is also good at 10 and 50 yards.
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-bp
Joined: June 5th, 2009, 4:21 pm

January 3rd, 2011, 11:07 pm #7

and all you're looking for is sharpness in the crosshairs

the head bop thing is for parallax at various distances, assuming you have the occular set once for good crosshair focus

adjusting the objective (whether with sidewheel or front ring) focuses the target image so that it is exactly in focus with the crosshairs.

you shouldn't ever move the occular once you have it set because doing so will change the setting at which your objective will focus on the same target - i know this from trial.

finding the right eyepiece setting is hard because the threads are so fine, that the hairs can appear to be in focus over a pretty large range of adjustment, maybe one or two turns. it's best to find the two edges of sharpness, mark them with a pencil on the scope, then set the ring between the two distances and lock the ring down

also remember that you must look away fromthe scope for about 5 seconds before looking through the scope, and make your judgement quickly after looking into the eyepiece, because your eye will immediately try to adjust to bring the crosshairs into focus.

while turning the occular can change your parallax, it's not the way to adjust for parallax. only turning the objective focus should be used to do that.

i've hounded an engineer friend who's an optic nut for all this info over the years. he's also a shooter. we were photographers together back when dinosaurs ruled the earth.

-bp
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Joined: May 14th, 2004, 4:11 pm

January 3rd, 2011, 11:14 pm #8

I adjust my ocular so that when I do a "head bop" (move my eye side to side) the crosshairs stay welded to the kz no matter where I place my eye. I do this at 30 yards because that's my normal zero distance. I did notice that when my ocular is adjusted for "zero crosshair movement" at 30 yards the crosshair isn't perfectly crisp. If I adjust the ocular so the crosshairs are perfectly crisp then I get a bit of crosshair movement as I move my head sise to side.

What I was wondering is if a "zero crosshair movement adjustment" (made with the ocular) at 30 yards is also good at 10 and 50 yards.
They recommend 11 yards or 1 to 5 yards more than the lowest focus setting your scope will dial down to.

http://ateam.100free.com/ateamh/A_Team_Parallax_adj.htm

Jeff P
Last edited by pad617 on January 3rd, 2011, 11:19 pm, edited 1 time in total.
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Joined: July 24th, 2010, 1:44 am

January 4th, 2011, 12:43 am #9

and all you're looking for is sharpness in the crosshairs

the head bop thing is for parallax at various distances, assuming you have the occular set once for good crosshair focus

adjusting the objective (whether with sidewheel or front ring) focuses the target image so that it is exactly in focus with the crosshairs.

you shouldn't ever move the occular once you have it set because doing so will change the setting at which your objective will focus on the same target - i know this from trial.

finding the right eyepiece setting is hard because the threads are so fine, that the hairs can appear to be in focus over a pretty large range of adjustment, maybe one or two turns. it's best to find the two edges of sharpness, mark them with a pencil on the scope, then set the ring between the two distances and lock the ring down

also remember that you must look away fromthe scope for about 5 seconds before looking through the scope, and make your judgement quickly after looking into the eyepiece, because your eye will immediately try to adjust to bring the crosshairs into focus.

while turning the occular can change your parallax, it's not the way to adjust for parallax. only turning the objective focus should be used to do that.

i've hounded an engineer friend who's an optic nut for all this info over the years. he's also a shooter. we were photographers together back when dinosaurs ruled the earth.

-bp
to put the crosshair ON the image plane so less than exact eye placement won't move the image of the crosshair relative to the target. As mentioned, when I use the "make the crosshair sharp while viewing the sky" method recommended by some, if I place the scope on a solid surface focused at 30 yards I can make the crosshair APPEAR to move simply by moving my eye from side to side. Now if I have the ocular adjusted properly I can move my eye from extreme right to extreme left and the crosshair will remain "welded" to the kz, however with my eyesight the crosshair will be SLIGHTLY fuzzy.

Where this comes into play is those pesky small kill zones where a less than exact positioning of the eye in the scope will make the crosshair appear where it isn't. If the adjustment is correct then the crosshair will remain stationary regardless of eye position. The issue for me is that I use a very light gun hold so I don't really get a solid cheek weld which gives me less than precise eye placement, so I'm TRYING to minimize one variable.

Bill, try this....
Mount your scope/gun in a stationary support, focus the AO at 30 yards, then look through the ocular from side to side. If the crosshair appears to move simply by moving your eye the ocular can be adjusted so the crosshair remains stationary. Obviously, if your eye placement is EXACT every time you look through the scope the ocular adjustment is only required to give you a sharp crosshair. By the way, adjusting the ocular will also affect the 30 yard focus on the AO so the range marks may need to be adjusted.

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Joined: July 24th, 2010, 1:44 am

January 4th, 2011, 12:54 am #10

They recommend 11 yards or 1 to 5 yards more than the lowest focus setting your scope will dial down to.

http://ateam.100free.com/ateamh/A_Team_Parallax_adj.htm

Jeff P
LOL.....I wasn't aware that this tutorial even existed! On the forums over the years I've read splatterings about the procedure. This does answer my question since I can adjust my ocular and do the "head bop" upstairs and it seems that the tutorial even recommends 11 yards and max mag. As mentioned, I've been doing the "head bop" adjustments at 30 yards, however I've also been using a 12x scope setting instead of the max scope power.
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