The specs for the PA are different than what my experience and many others have, I don’t know why it says that in the specs, but I assure you that the PA has over 30 Mils of total adjustment and the Argos has just over 24.
Oh, interesting. Is it possible that the "extra" elevation adjustment (12 mils for the PA and 6 for the Athlon) isn't evenly distributed above and below optical center? Maybe you got lucky with the distribution on the PA and/or unlucky with the Athlon?
Since your rifle is already zeroed, you can find the optical center pretty easly, by first calculating how much elevation travel you lost by zeroing the rifle, than subtracting that amount from the 5.9 mils that you gained from the 20MOA rail. Dial up that much and you'll be at the optical center of the scope. From there, you can dial up and down to see how much range the scope actually gives you in each direction.
The ballistics calculator at
https://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi will tell you how much elevation travel you lose by zeroing your rifle if you give it this info:
- ballistic specs (or name of the bullet or factory cartridge)
- muzzle velocity (there's a chart at http://ruger1022.com/docs/22lrballistics.htm if you don't have a chrono)
- scope height (distance from bore center to scope-tube center)
- zeroing distance
I just tried it out. For a rifle shooting factory CCI .22LR Standard Velocity cartridges at 1070 fps MV, with a scope height of 3 inches and a 50-yard zero, the calculator says I'll lose 13.568 MOA, which is 4.0 mils, of upward travel by zeroing the rifle.
If I subtract that from the 5.9 mils that I gain from a 20MOA rail, I get 5.9 - 4.0 = 1.9 mils.
You say your zeroed PA has 19 mils of up travel, and the zeroed Athlon has 9 mils. So if you zeroed your scopes under the same conditions as in my example, the PA would have 19 - 1.9 = 17.1 mils of elevation above optical center (meaning that if there were equal travel available up and down from optical center, that scope would be providing
34.2 mils of total elevation), and the Athlon would have 9 - 1.9 = 7.1 mils of elevation above optical center (
only 14.2 mils total elevation if the up/down travel was symmetric).
Those are both odd results; they don't match up with your 30 mil / 24 mil numbers or with the published 18 mil numbers. They could be correct if both scopes have asymmetric up/down travel, but I'm no scope expert, so I have no idea how likely that is. The only other explanations I can think of are:
PA:
What if PA's published spec for "total elevation" -- 60MOA / 17.8 mil -- is actually the scope's available UP elevation? If that were true, the total elevation would really be around 35.6 mils.
(35.6 / 2) + (5.9 - 4.0) = 17.8 + 1.9 = 19.9 mils available elevation, which is around what you reported.
Athlon:
Let's say the Athlon really does have "over 24 mils" (maybe 24.5 mils) of total elevation as you claim, despite their published 18-mil spec. What if your "20MOA" rail is actually a 0MOA rail?
In that case, available elevation using my ballistic specs would be (24.5 / 2) + (0 - 4.0) = 12.25 - 4.0 = 8.25 mils available elevation. Which isn't the 9 mils that you reported, but it's close. And if your scope height's a little lower or your muzzle velocity's a little higher than my example, you might be using only 3.25 mils rather than 4.0 to zero the rifle, in which case the 0MOA rail calculation would exactly match what you've reported.
Hmm, this post was a lot longer than I thought it would be.
