So that would indicate an error at 140 yards of 20”. Even if we go with half that at just one inch that would still be an error of 10” at the 140 yards. If we go farther then the error is magnafied more! 280 yards is now a 20” error which is huge in my opinion. Just because a scope is variable power or has parallax adjustment doesn’t make it bad or a gimmick. Setting the parallax for 100-150 and leaving the magnification on its lower setting is like having the fixed power non adjustable objective scope. If you need to shoot fast it will be the same as the scopes that have been described here. But if you need more magnification for a longer shot you have the ability to increase power and adjust parallax for more precise shooting. Most skilled shooters also adjust parallax looking thru the scope and not reading numbers on a dial. Most realize that everyone’s vision is different so the numbers are just an approximation that will be different for everyone! Scopes have come an extraordinary way in the last thirty years. I’m old and remember the set it and forget it deal but those days are long gone. Lens quality and coatings coupled with extremely advanced machining and advancements in assembly techniques have brought optics to an entirely new level. Competition between manufacturers has led to lots of R&D resulting in constant advancements in the optics world. Would anyone have imagined you’d have a laser rangefinder with on board ballistic calculator the size of a small pair of binoculars that could range a target at 2000 or more yards 30 years ago? Stick with a fixed power non adjustable objective scope but flexibility is not a bad thing or a gimmick but rather progress and advancement in optics.I like a parallax adjustment mainly because it lets me use quality centerfire scopes on rimfires to get maximum accuracy at shorter ranges. But the guys who miss with a .22 at 20, 30, 50 yards...by a foot or more!...and then try to use parallax as an excuse are hilarious.
Take whatever scope you want, set it at whatever magnification you want, put it in a solid rest like a shooting rest or cleaning cradle, and then just look through it at any target you want and at various ranges. Move your head back and forth, up and down, and watch the crosshairs move on the target. See how much difference it makes at various ranges. It ain't much. You'll quickly see that all those frightening parallax errors that you read about are absolute maximums within the range of possible error. You need to have your head so far off center for those maximums that you aren't even seeing a circular view of view anymore, you're looking at a crescent moon shape.
Of course it's not possible to hold your eye perfectly centered for every shot...we're humans, not robots...but it's certainly possible to be aware of this issue and to incorporate this awareness into your shooting practice. You learn and practice and perfect your hold, your breathing, your trigger squeeze; do the same with positioning your head behind the center of the dang scope. If you don't see a nice even black circle around the field of view...you're not centered; simple as that. You will quickly learn to keep that nice symmetrical ring around the field of view, and bingo! No more parallax...or, rather, only a very small amount, in the middle of the possible much larger range that could exist if you ignore your head position.
One less goofy unnecessary adjustment on your scope...one less thing to go wrong...one less cause for concern as you set up a shot.
Incidentally, lots of guys play with the parallax adjustment, setting it exactly to 200 yards or whatever after taking a laser rangefinder reading to get that distance. Sometimes that is perfect; usually, the setting is off a bit one way or the other. Sometimes it's so far off that the image is visibly blurry! If you're planning on fretting and worrying about parallax, you really should range a number of targets and then test the settings on the parallax dial against reality. Yeah, by resting the rifle and then bobbing and weaving your head behind the scope like before. You might find that a 300-yard target needs the parallax knob to be set halfway between 200 and 300, or between 300 and 400, to actually give you a parallax-free view at 300. The difference in practical accuracy will be small...probably just as small as not having an extra knob on the scope to begin with...but, hey, you wanted and paid for that knob, because you wanted the ultimate in accuracy, so...enjoy!
Edited to add: I just did a quick and dirty experiment. I took a Bushnell fixed 10X Tactical scope, an inexpensive but decent little scope that I have on a .22 bolt gun used at 100 yards almost exclusively. I'm pretty sure it's specs call for a 100-yard parallax setting on it, and that seems to line up with my experience shooting it. Set it up solidly and got the crosshairs centered on a birdfeeder 14 yards away. I then tried to see how much parallax error I could create by purposely moving my head around behind it.
I got a maximum "drift" of the crosshairs on the birdfeeder of about 2 inches from left to right. Couldn't get any more because any further movement of my head would complete obscure the field of view into blackness. Even getting that required me to be so far off center that I was looking at only a tiny fraction of the once-round field of view. Put another way, the maximum error I could introduce, the maximum distance the crosshairs could drift from my desired point of aim...was one inch. Just holding my head carefully enough to see a round view eliminated almost all of that.
A 10x scope...aiming at extreme close range, where parallax is at its worst...required a concentrated and conscious effort to produce an aiming error of one inch on the target.
Come on, people. The marketing guys are taking you for a ride. Spend the money on more ammo rather than unnecessary gadgets, practice more, and go hunting knowing that if/when you miss...it's not due to parallax.
Scopes without parallax adjustment question.
- Thread starter 45C
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I'm not pretending to understand the details of the optical science that explains this stuff. I am simply stating what I've seen with my own two eyes. The potential parallax error when shooting at closer ranges than the parallax setting in the scope is far, far greater than when shooting beyond that distance.
The parallax calculator posted earlier in this thread agrees. Punch in the numbers for a 40mm scope with a fixed parallax setting of 100 yards, being shot at a target only 10 yards away. It shows a maximum potential parallax error at 10 yards to be just over 6.7MOA, which at ten yards is about 0.7 inches. That's the maximum you could get, with your eyeball as far over to the side as you can get it and still see the target. In practice, you will do much, much better by simply paying attention to your head positioning.
But look at the numbers out to 900 yards. That same scope shot at 900 shows a maximum possible error of 0.67MOA, which is a wee bit over 6 inches. Again, that's the worst error possible, and in practice will be much less.
Shooting this setup at 300 yards has a potential maximum error of way less than 2 inches.
Less calculating, more actual looking through a scope and pulling a trigger is the key here. In fact, you don't even need to shoot the gun! Just look through the scope of your choice at some target with a grid of known dimensions; it's that simple. Parallax is right there for you to see with your own two eyes. It exists, definitely, and can be measured and quantified with that grid. It can be lessened with proper shooting technique, absolutely. It can be further controlled/reduced/eliminated with an adjustable-parallax-setting scope, unquestionably. It's likely more of a bugaboo with today's trend towards higher-magnification scopes. Probably most importantly, using that grid target will show you not only that parallax error is much less than many think it is, but also that your actual parallax error in practice is far, far less than that "potential maximum error" that your calculations warn about.
If you are shooting for precision at extreme ranges...whether extremely long or extremely short...you can derive some benefit from another knob on your scope. For the vast majority of shooters, the benefit is very small. I could even make a case for the idea that an adjustable parallax is a crutch that negates the need for practicing that aspect of shooting...i.e. proper head positioning...and thus might even hinder your performance if/when you ever find yourself sighting through a stone-age non-adjustable scope.
If you are the kind of shooter who knows he needs a parallax adjustment and what it can do for you...you probably will gain some benefit overall from having one.
If you aren't sure and/or don't understand it but just think you might need one because all the cool kids have one...I'll bet folding money that you don't need it.
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Coincidentally, I was mounting a scope today with a parallax adjustment and it made me think of this thread. Take one such scope...it doesn't matter whether it's an adjustable collar at the objective or a side-adjusting dial...and have a look at it. Changing the parallax setting from, say 25 yards to 50 yards involves a relatively huge amount of movement on the adjusting collar or dial; the lens group being moved to make the image coincide with the crosshairs is going a long way inside the scope. But look at the tiny amount of movement required to change the parallax from 100 to 200, or 200 to infinity. The lens moves hardly at all.
So since parallax is caused by the discrepancy in the locations of the crosshairs and the focused image, it's obvious that at short distances, the two are potentially much farther apart and thus if not adjusted properly, you are looking "around" the crosshairs at the image a considerable distance away, thus creating a large degree of parallax. But at further and further distances, the image and crosshairs are not really that far apart and so the parallax error is vastly smaller than the short range example.
It's not just a simple direct relationship between distance and parallax; doubling the target distance does not double the potential parallax, not even close.
So since parallax is caused by the discrepancy in the locations of the crosshairs and the focused image, it's obvious that at short distances, the two are potentially much farther apart and thus if not adjusted properly, you are looking "around" the crosshairs at the image a considerable distance away, thus creating a large degree of parallax. But at further and further distances, the image and crosshairs are not really that far apart and so the parallax error is vastly smaller than the short range example.
It's not just a simple direct relationship between distance and parallax; doubling the target distance does not double the potential parallax, not even close.
Well apparently all the many hundreds or thousands of shooters in both rimfire and centerfire matches or BR shooting that I’ve shot with or seen shoot all use parallax adjustable scopes. There’s a place for both but for what I do it’s adjustable for most things other than a few hunting rifles.
