I was perusing the pages of the famed field publication last night and came across a Q&A Section that caught my eye. Mr. Petzel, long-time "gun guy" for the magazine, got a question many of us have given some thought to over the last few months. His answer was no surprise although it may be worth noting in relation to our debate.
Here's the section -
(http://i28.photobucket.com/albums/c226/bradleysettle/laxa_zps84256ac3.jpg)
Perfectly true.
But, the last time I checked, AQT targets for each stage are quite a bit smaller than coyotes.
For small targets, especially at 25 meters, parallax can be a big deal, especially for older shooters who wear progressive lenses.
Parallax is something that does matter under certain conditions. The key is knowing when it does matter!
---gb
I had assumed Slim was talking about the much more important matter of the best gun-related movie scene ever. ;)
My personal favorite is probably the "Fill your hand" scene from True Grit. I think a discussion about this will be way more fun than a discussion about parallax.
If the goal were "minute of coyote" out to 300 yards, I would agree with the author. If we assume a 100 yard fixed parallax scope, which is common, parallax errors between 100 and 300 yards would be quite small (I'm sure Guntuckian can do the math for us). At closer ranges, where parallax matters a great deal more, the coyote is large enough that a 3 or 4 MOA shift due to parallax would not matter, since a coyote would be more like a 16 MOA target at 50 yards.
For Appleseed purposes, parallax errors are much greater at shorter distances and the target is rather smaller than a coyote. It's ultimately all about angles, and the closer the target the more acute the angles are, and the greater the chance for parallax errors to come into play.
It's important to remember that as long as the position of the eye behind the scope is exactly the same every time, parallax errors are non-existent at any range with any scope. They only come into play if the eye position changes slightly, which for new shooters it almost certainly does, and even for experienced shooters eye position will change as shooting positions change.
So if your point was to support the position that parallax doesn't matter, then if we're shooting coyotes out to 300 yards I agree. If we're shooting Appleseed targets at 25 meters then the correct answer is different.
:DH: :DH: :DH:
I thought the debate was over. ???
Some highlights:
Parallax exists. It is the result of improper and/or inconsistent eye/sight position/alignment. Its can be marginalized, mitigated and/or eliminated entirely by the use of a parallax adjustable scope and/or exercising proper/consistent sight alignment.
Some people care more about parallax some people care less about parallax.
Some people may have a medical condition which may exaggerate the effects of parallax and/or not be physically capable of maintaining a consistent eye/sight position/alignment.
Appleseed's targets are big enough that if a shooter maintains a reasonably consistent eye/sight position/alignment they should score hits. "V's" require a greater level of attention and/or vigilance.
Appleseed does not incorporate a dedicated POI on the subject of parallax because it is understood that if one executes the fundamentals, it is not detrimental to attaining the base level of accuracy - 4 moa.
Appleseed instructors should know what parallax is, understand its signs/effects and proper techniques, so as to facilitate the coaching of individuals in overcoming the detrimental aspects of the condition.
New shooters, young shooters, and others may have difficulty grasping the concept of parallax and/or effectively correcting the the resulting issue(s). Instructors should work with shooters to help them understand and implement a consistent eye/sight position/alignment. Instructors may recommend a parallax adjustable optic, assuming conditions for such recommendation exist.
Proper fundamentals are preferred to equipment upgrades.
Some people question whether utilizing parallax adjustment is an unfair advantage in attaining Rifleman qualification.
Some people question whether utilizing magnified optics is an unfair advantage in attaining Rifleman qualification.
Some people recognize that optics and/or optics with parallax adjustment may provide an unfair advantage in attaining Rifleman qualification, but that the fundamentals still apply.
Some assert that they are necessary for some to overcome certain medical conditions.
Some assert that the standard for qualification is what it is and was established in a manner ignorant of individual equipment set ups.
Some assert that there are more important things to worry about.
Bottom Line:
The subject of parallax and need for mechanical parallax correction should be examined on an individual, case-by-case basis.
Quote from: Moylan on February 09, 2015, 03:23:48 PM
I had assumed Slim was talking about the much more important matter of the best gun-related movie scene ever. ;)
My personal favorite is probably the "Fill your hand" scene from True Grit. I think a discussion about this will be way more fun than a discussion about parallax.
"Are you feeling lucky, punk?" has to be considered, I think.
Quote from: EZ3 on February 09, 2015, 10:45:03 PM
"Are you feeling lucky, punk?" has to be considered, I think.
That's exactly what I find myself saying just about every time I feel the parallax kicking in.
Which seems to be happening more and more frequently, the older I get.
Probably need a bit more of the old metamuecil.
Quote from: floydf on February 09, 2015, 11:14:04 PM
Quote from: EZ3 on February 09, 2015, 10:45:03 PM
"Are you feeling lucky, punk?" has to be considered, I think.
That's exactly what I find myself saying just about every time I feel the parallax kicking in.
Which seems to be happening more and more frequently, the older I get.
Probably need a bit more of the old metamuecil.
;D ;D
Dead or alive, you're coming with me.
The enemy cannot PUSH the button if you disable his HAND. MEDIC!!!!
Quote from: SPQR on February 10, 2015, 12:56:33 AM
The enemy cannot PUSH the button if you disable his HAND. MEDIC!!!!
That's not a gun scene!
Harley: This here's a Ruger, Super Blackhawk, .454 conversion.
Marlboro: That's too much gun for you, Harley.
Harley: It's what I learned on.
Marlboro: (laughs) Nobody learns with a converted .454!
Harley: I did.
Marlboro: Well... that explains it.
Seeing as about 20% of any given movie is all about gunplay, there's a lot to choose from...
Personally I might go for the climax of Zulu. Martini-Henry and Webley thunder!
At the risk of beating this horse even further, I thought I would take one more crack at explaining why this issue can be important for at least instructors to have a good understanding of. Instead of discussing this in terms of rifle scopes, though, I want to present a different scenario.
I think any Rifleman would agree that sight alignment is important when using aperture sights. The tip of the front post needs to be aligned in the center of the aperture. Nobody questions this. Anyone ever think about WHY the post needs to be in the center of the aperture?
The obvious and simple answer is that if the post isn't centered, or at least reasonably centered (more on this in a minute) in the aperture, shots won't impact where they are supposed to. They will hit the target left or right, higher or lower, than the point of aim. Bring the tip of the post back to the center of the aperture and this goes away. So far so good, this is pretty much Appleseed 101 stuff.
This one may cause some heads to be scratched, but if you think a bit about WHY that post needs to be centered, the answer is....here it comes....parallax errors. The shooting error which is encountered by the shooter if the sights aren't aligned with the target (sight alignment and sight picture both need to be correct) is caused by parallax.
Wait, what? Parallax with iron sights? What IS parallax, REALLY? From the Wikipedia page on parallax we find a simple definition:
QuoteParallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances.
Don't believe me? Try this experiment. Pick up a rifle with aperture sights, and get a good sight picture with good sight alignment on something. Now nudge your eye around, high or low, left or right. Look closely at what the tip of the front sight does in relation to the target.
What you'll generally see is that with fairly small eye movements, the tip of the post will not move at all. As you move your eye further, though, you'll see the tip of the post move in relation to the target. This is, obviously, why the post needs to be centered in the aperture. If it's not, if our head position varies, the apparent position of the target changes in relation to the position of the front post. This is a parallax error. With iron sights.
Now it turns out that the relation between the size of the aperture and the size of your iris affects this parallax error. To the extent that the aperture on the rear sight is smaller than the iris in your eye, the "center" of the aperture is more forgiving of small changes in eye position. The post really only needs to be in the general vicinity of the center of the aperture to avoid errors on the target. It doesn't actually have to be "dead center". The science behind this is a bit on the complex side, so I won't go into it here, but it's certainly true that putting the post "close" to the center of the aperture is "good enough". The size of the rear aperture in relation to the size of your iris defines the size of this "good enough" zone.
It also turns out that the parallax error you find when sight alignment is poor using aperture sights is exactly the same as the parallax error you find when using a rifle scope. The big difference, though, is since a scope uses lenses to focus light, we can't SEE that the focal points inside the scope are out of alignment the way we can SEE that the aperture sights are out of alignment. All we can usually see is what's on the target.
And as the Wikipedia definition suggests, this parallax error is much less for distant objects than it is for nearby objects. This is why the potential for parallax error is of little consequence when shooting a coyote at 300 yards, but is potentially much more significant when shooting an Appleseed target at 25 meters.
Don't know if that clears anything up or confuses it more, but there it is.
.....YOU!!!
-Shieriff Stockdale facing Clint Eastwood in Palerider
"Yeah, I bet you have...." The last thing Greedo ever hears.
Sorry, best gun-related movie scene was in Tombstone when Billy Clanton looked at Doc Holliday and said "you're so drunk you can't even see straight" and Holliday pulls out another revolver and says "I got two guns, one for each of ya."
Quote from: Rocket Man on February 10, 2015, 01:06:18 AM
Harley: This here's a Ruger, Super Blackhawk, .454 conversion.
Marlboro: That's too much gun for you, Harley.
Harley: It's what I learned on.
Marlboro: (laughs) Nobody learns with a converted .454!
Harley: I did.
Marlboro: Well... that explains it.
Seeing as about 20% of any given movie is all about gunplay, there's a lot to choose from...
Personally I might go for the climax of Zulu. Martini-Henry and Webley thunder!
I don't remember any gunplay in sisterhood of the traveling pants but I could be wrong. however care bears the movie was especially graphic. :~ **)
"You're bleeding, man. You're hit."
"I ain't got time to bleed."
"Oh... Okay..." (Shoots volley of grenades) "You got time to duck?"
And the minigun turning a jungle into a meadow.
Sorry folks, the final shootout from Open Range for the win.
You're the one who shot our friend?
Yeah, I shot the boy too and I enjoyed it
Booom, right between the eyes
"This is my safety, sir."
.38... .39, whatever it took.
The Sundance Kid providing "cover" at the end of Butch Cassidy And The Sundance Kid.
Another in the same movie: "I'm better when I move."
I'm intrigued by how many more comments we seem to get on entertainment than either history or marksmanship. One of the first things that I did after attending my first Appleseed back in 2008 was to get rid of my TV.
Quote from: jmdavis on February 11, 2015, 11:01:07 AM
I'm intrigued by how many more comments we seem to get on entertainment than either history or marksmanship. One of the first things that I did after attending my first Appleseed back in 2008 was to get rid of my TV.
Shakespeare is fabulous entertainment. What if we quoted Shakespeare instead? Would that be OK? :) ;D :) ;)
I put my initial comment about the gun scenes in movies because we've had some very long threads about parallax before and they haven't always been completely friendly. Just looking to lighten the mood a bit.
Quote from: jmdavis on February 11, 2015, 11:01:07 AM
I'm intrigued by how many more comments we seem to get on entertainment than either history or marksmanship. One of the first things that I did after attending my first Appleseed back in 2008 was to get rid of my TV.
While I count myself a serious student of marksmanship and seriously enjoy this tread on a day to day basis for that reason, it was a relief to get to have some sort of light exchange with my fellow instructors after all of the heavy duty acrimony going on elsewhere. This thread reminds me why I enjoy AS so much.
That's a good point Shooter30-06. But why does the discussion of serious principles of marksmanship or history create acrimony? The acrimony, in my experience comes from trying to limit and control people. We can talk about what we like. But of late, topics have tended toward the entertainment rather than the education side.
It's not just parallax that leads to acrimony, it also goes for history and the study of history. We went through how many pages talking about a History Channel pseudo docu-drama and extrapolating from it. But we have REAL documents (those depositions that we talk about in the third strike) to tell us what was happening. On the marksmanship side we have resources from AMU, MTU, Jim Owens, and these are resources that Appleseed was developed from.
As time goes on, it seems to me like the Appleseed instruction gets watered down and you reach a point where instructors fail to understand WHY we do something. That is a problem that we can either ignore or address. But choosing to ignore it has not led to an improved program. People forget the concept of TPI (military training doctrine), they forget where the idea of using a plastic army man to explain NPOA comes from (Jim Owens, "Sight Alignment, Trigger Control, and the Big Lie"), they lose sight of the instruction that the support elbow should be as close to under the rifle as the shooter's body type will allow, they describe a turkey neck but fail to note that the object is to center the eye behind the rear sight in a repeatable manner to assure sight alignment, they present sitting as cross legged, cross ankle and open leg and then say that those are in order of stability, they don't understand that a sling that is too tight will lead to cant and force the use of other muscles to correct it, they don't understand that "dragging wood" may or may not be an issue and that an instructor must look at the muzzle and the target to determine if it is or not.
I guess in short what get's lost is that there is more than one way to do many things but that certain things are more important (sight alignment and trigger control for instance) than others (elbow directly under the rifle, or neck extended).
Moylan,
Read the Shakespeare quote. I don't present it as entertainment but as philosophy and leadership. Philosophy that I am willing to live by. But have as you will.
Quote from: jmdavis on February 11, 2015, 11:01:07 AM
I'm intrigued by how many more comments we seem to get on entertainment than either history or marksmanship. One of the first things that I did after attending my first Appleseed back in 2008 was to get rid of my TV.
"Lord, make me fast and accurate..."
aim small, miss small...
Quote from: jmdavis on February 11, 2015, 12:53:56 PM
Moylan,
Read the Shakespeare quote. I don't present it as entertainment but as philosophy and leadership. Philosophy that I am willing to live by. But have as you will.
jmdavis,
It was just a joke, jmdavis. Just a joke. Again, lightening the mood. Or trying.
As it happens, I have read those lines before, and in fact even a few other lines from Shakespeare. If you ask my homeschooled children about it, they'll recite the whole speech for you. :) I prefer the Branagh version to the more recent version from The Hollow Crown, but both have their pluses and minuses. My view is that Shakespeare ought not to be
read, but rather to be
heard. Of course, one could always address that by reading it aloud to yourself. Either way, Shakespeare's works were written as entertainment for the masses. Sort of like today's movies. Thus my little joke. Just a joke. Not a deep reflection on the nature of things. Although as it happens, I have some familiarity with philosophy, too. :)
You ask why discussing serious principles of marksmanship or history creates acrimony. I don't know. But I note that it does. Even jokes can sometimes bring responses that don't seem very friendly. ;)
The Branagh is good. I also recall a Richard Burton version from 1951, that I saw in the 80's in a Grad class.
https://www.youtube.com/watch?v=TU7NrnLsr5g
Here's Olivier's 1944 version. I didn't realize it was on youtube,
https://www.youtube.com/watch?v=P9fa3HFR02E
Quote from: jmdavis on February 11, 2015, 01:23:49 PM
The Branagh is good. I also recall a Richard Burton version from 1951, that I saw in the 80's in a Grad class.
https://www.youtube.com/watch?v=TU7NrnLsr5g
Here's Olivier's 1944 version. I didn't realize it was on youtube,
https://www.youtube.com/watch?v=P9fa3HFR02E
I didn't even know there was an Olivier movie version. I'll have to get ahold of that. Thanks!
I also notice the date on that--1944. It must have had special power for the people of England in the midst of the War.
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