How does one verify scope magnification?

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Potashminer

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Today, I received two scopes sold as "3 to 9 power" from CGN'ers. Items were as described, and prices were fair - once again, very smooth transactions on CGN. Upon examination, however, the Weaver scope is actually marked as "Weaver V12-B USA", (see first picture below), yet the power ring only goes from 3 to 9. (See second picture). When cranked up to highest power, items at 25 to 300 yards appear larger through the Weaver than when viewed through the 3-9 Burris at "9" power.
I am all good if this is actually a 4-12 power scope, but it got me to wondering how would one go about verifying the magnification rating of a scope. So, a Weaver K3 claims to be "3" power - how do I check that? A "1.75 to 6" versus a "2 to 7" power - how would I confirm that they are not actually 2.1 to 6.5 power?
I am, of course, assuming that "one power" is my eyesight. So what or where do I measure to tell that my optical device is actually magnifying 3x, 6x or 10x??

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The magnification rating tells how many times closer an object appears. So with a 9x scope an object 900 meters away appears to be 100 meters away.

So get two identical objects, place one 10 meters away and the other 90 meters away lined up so you can see both of them side by side. Then look through the scope with one eye at the farther object while looking at the closer object with your naked eye. If they look the same size, it's a 9X.
 
Interesting. I had a 3-9 that appeared less magnified than another as well. I wasn't sure how I could really tell so I didn't worry much about it.
 
bearkilr said:
http://precisionrifleblog.com/2014/06/30/how-to-measure-the-apparent-magnification-of-a-scope/
Click to expand...

Awesome reference, bearkilr. I think I follow the physics, but it sort of begs the question - if I need an optic device capable of measuring 100.00 yards +/- 1/32", and a digital camera as the author describes, with the associated software to analyze the images, essentially most of us are kind of stuck accepting the label on the box - they could call it 4.5 to 14, 4 to 12, even 6 to 18 or 3 to 9, and we really don't have a practical way of verifying that it isn't actually 3.7 to 11.
DB, your solution is mentioned in the Precision Rifle article as a 1918 solution (by the predecessor of today's ASTM, no less!), and, still, to my mind, might be the most realistic choice that us mortals have.
 
In my opinion you got took, probably not intentional but a 4 to 12 or 16 to 32 goes to those numbers.If you like it keep it if not send it back.My 3 cents.
 
Potashminer said:
Awesome reference, bearkilr. I think I follow the physics, but it sort of begs the question - if I need an optic device capable of measuring 100.00 yards +/- 1/32", and a digital camera as the author describes, with the associated software to analyze the images, essentially most of us are kind of stuck accepting the label on the box - they could call it 4.5 to 14, 4 to 12, even 6 to 18 or 3 to 9, and we really don't have a practical way of verifying that it isn't actually 3.7 to 11.
DB, your solution is mentioned in the Precision Rifle article as a 1918 solution (by the predecessor of today's ASTM, no less!), and, still, to my mind, might be the most realistic choice that us mortals have.
Click to expand...

I think most manufacturers list actual magnifications or at least they're available online. I know I've seen it for the lowest and highest power on variables.
However, measuring an unknown like yours seems to be a very involved process most of us probably wouldn't care to tackle!
 
It really goes to what we actually "want" to know. Not just for an "unknown" like mine, but what about any other scope?? I have seen threads here expounding on the merits of 1 to 4 vs. 1.5 to 5 vs. 1.75 to 6 as the perfect setup for some particular application, but, it strikes me, this is all "fuzz" if there is not a standardized way for the consumer to know that your 1 to 4, turned right down, is different than his 1.75 to 6.0, also turned down. That, by the way, is assuming a higher end manufacturer - all bets are off for "economy" brands...
 
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