So, when you are "shooting drills" do you already know the range of the target? Or do you have to range it? I'm not entirely familiar with the sport. Also, if you're timed and don't have time to adjust the parallax, and you shoot outside the optimal eye box, how are you correcting for parallax? Or are the ranges and target size such that parallax is not a serious issue?

The following link is to a video by Jacob Bynum of Rifles Only, when he was doing videos for Snipers Hide. The video covers some import points:
- For a shooter with good fundamentals, the rifle's zero doesn't change when shooting positions change.
- When the shooter isn't positioned so that he's shooting at the sweet spot of the eye box, and when parallax is off, there is a noticeable change in Point of Impact. This part of the video starts at 1:20, with the impact shown at 1:50.

Offgrid's points on dot drills are dead on. Regardless of shooting type or rifle equipment -- accuracy improves and POI is closer to POA when cheekweld/eyebox/eye relief is as close as possible to perfect.

shooting positions & parallax

What's he's calling "edge to edge clarity" is what I called a full field of view. Much deviation from that and you get occlusion from the scope tube - blocked edges. There really wasn't anything he said that was new. As he said, it's pretty much all fundamentals.

My question was how parallax is compensated for if you're not using your parallax adjustment. I'm under the impression from an earlier comment that parallax is an issue in these drills. That guy in that video took a shot and determined his point of aim and point of impact were off due to parallax and compensated for it. Good enough. But the guy running the drill was taking single shots at target. I don't know how big the targets were or the distances to know if parallax was was an issue. I heard a guy calling "hit."

If your target is big enough, parallax is not really an issue. I know parallax IS an issue if you are shooting at a small target with less than perfect cheek weld at a distance that doesn't comport to your parallax setting.

I'm just wondering how the parallax issue really fits into this whole eye box discussion.

quote:

Originally posted by sigfreund:
The only scope I’ve had in recent times without the feature was a Leupold Mark 4 1-6×. I don’t know what the factory setting was, but probably 100 to 150 yards.

Scopes like yours don't have enough magnification to need adjustable parlax. I read somewhere that paralax is set at about the distance you mentioned, but I can't remember where I read it. There was some lively discussions on the service rifle boards when optics were first allowed because everyone was assuming paralax was going to be a bigger problem than it turned out to be. The current top of the line March service rifle scope is a 1-4.5x24 and doesn't have adjustable paralax.

The scope I was referring to was really a Mark 6, not 4, but it's true low powered scopes don’t need parallax adjustments.

My understanding of dot drills is that they usually use a single sheet of paper with the requisite number of dots and of course set up at a single distance. They don’t, therefore, require changing the parallax setting after setup.

From what I’ve seen of Precision Rifle Series competitions, the targets are typically set at different distances, but they are all at such long ranges that evidently no one needs to adjust parallax during a stage. I’ve seen competitors change their elevation settings as they engage different targets, but not parallax settings. In the old days when the parallax setting was fixed at a relatively long distance, the fact that it couldn’t be adjusted never seemed to bother hunters. Of course in the old days most fixed power scopes were 4×—so much so that when I settled on a 6 power Lyman for my first high powered rifle, a Ruger 77 in 270, it was unusual enough to elicit the occasional remark.

With the scopes on my precision rifles, once the target distance gets beyond a couple of hundred yards the parallax setting doesn’t seem to matter much, especially at lower magnification settings.

some of these optical terms extend outside the riflescopes and target shooting.
as the op has stated. all things being equal on paper.

at the same magnification.

if two scopes state the same exit pupil and the same eye relief range (say 3.5-3.7") the more relieving eye box could either be the relation of the ocular and objective lens (diameters as well as their distance from each other). or simply a larger ocular lens delivering more light giving your eye a "bigger box" to get a focused sight picture, not saying this is the only way it can happen.

a couple of factors can change the eyebox. without doing a bunch of formulas... the higher the max magnification the larger the objective and ocular should be, with the ocular not being too much smaller in proportion to the objective. at some point...if your riflescope looks like a Meade pointing at the moon...you've gone too far.

quote:

Originally posted by sigfreund:
From what I’ve seen of Precision Rifle Series competitions, the targets are typically set at different distances, but they are all at such long ranges that evidently no one needs to adjust parallax during a stage.

It all depends on the stage.

A stage with targets that are all fairly distant, with distances that don't vary much from closest to farthest, where magnifications are moderate, where time constraints are tight -- then yes, parallax often isn't adjusted while shooting

A stage with targets with distances that vary greatly, where higher magnification levels are used, where the targets are pretty small, when time constraints are more generous -- then parallax can be tweaked from shot to shot.

quote:

Originally posted by Micropterus:
I don't know how big the targets were or the distances to know if parallax was was an issue.

Jacob's demo was done at 100 yards with standard 3" pasters. Jacob did not state where the flawed parallax was set, but I do know it was quite a ways from 100 yards. The result of poor sight picture plus flawed parallax was 1.5" POI shift at 100 yards.

quote:

Originally posted by Micropterus:
If your target is big enough, parallax is not really an issue. I know parallax IS an issue if you are shooting at a small target with less than perfect cheek weld at a distance that doesn't comport to your parallax setting.

I'm just wondering how the parallax issue really fits into this whole eye box discussion.

If the target is big enough and close enough, then the shooter can get away with a whole lot of flaws in technique. Along the lines of shooting the side of a barn from inside the barn.

Jacob's demo shows how multiple errors can add up to producing a pretty significant POI shift.

quote:

Originally posted by sigfreund:
My understanding of dot drills is that they usually use a single sheet of paper with the requisite number of dots and of course set up at a single distance. They don’t, therefore, require changing the parallax setting after setup.

Yes, that's correct. The test/challenge of a dot drills is to test our ability to build a consistent cheek weld, same pressures and hit a target.


Unfortunately all this eye box stuff can't be found in manufacturers specs. As I mentioned earlier, to my eyes there is no better eye box then the Hendsolt, it's also almost parallax free. Compare the manufacturers specs of that scope to to others.

https://www.eurooptic.com/carl...ocal-riflescope.aspx

If this scope was 20-22X and a different reticle...

quote:

Originally posted by fritz:
If the target is big enough and close enough, then the shooter can get away with a whole lot of flaws in technique. Along the lines of shooting the side of a barn from inside the barn.

Jacob's demo shows how multiple errors can add up to producing a pretty significant POI shift.

Ya, shooting a deer with a 6-7" vital target at 50yds, all this eye box stuff doesn't really matter. Same shot at 500yds, matters along with a pile of other things.

quote:

Originally posted by offgrid:
If ... a different reticle...

Yeah, even I don't think much of that one.

quote:

Originally posted by fritz:
Jacob's demo was done at 100 yards with standard 3" pasters. Jacob did not state where the flawed parallax was set, but I do know it was quite a ways from 100 yards. The result of poor sight picture plus flawed parallax was 1.5" POI shift at 100 yards.

Not the first guy, the second guy running the course.

quote:

Originally posted by Micropterus:
Not the first guy, the second guy running the course.

From what I remember, the targets are relatively close on that course of fire -- generally in the 200-300 yard ballpark. That video was uploaded 10 years ago and Jacob has moved things around. I'm on site, so maybe I can get an idea tomorrow.

quote:

Originally posted by fritz:
...the targets are relatively close on that course of fire -- generally in the 200-300 yard ballpark.

It's been too long since the video was shot to be exact, and props are now in different locations. The shot with the "hit" call was likely in the 200-250 yard ballpark. The shots with no call could have been close-in paper targets -- or shots on steel which probably were misses.

quote:

Originally posted by SgtGold:

quote:

Originally posted by sigfreund:
The only scope I’ve had in recent times without the feature was a Leupold Mark 4 1-6×. I don’t know what the factory setting was, but probably 100 to 150 yards.

Scopes like yours don't have enough magnification to need adjustable parlax. I read somewhere that paralax is set at about the distance you mentioned, but I can't remember where I read it. There was some lively discussions on the service rifle boards when optics were first allowed because everyone was assuming paralax was going to be a bigger problem than it turned out to be. The current top of the line March service rifle scope is a 1-4.5x24 and doesn't have adjustable paralax.

That last bit about the March 1-4.5X24 is incorrect; it does have a side focus. About the only March scope that doesn't have a side focus is the 1-4X24.

quote:

That last bit about the March 1-4.5X24 is incorrect; it does have a side focus. About the only March scope that doesn't have a side focus is the 1-4X24.

I don't know how I didn't see it the first time I looked. I stand corrected.