Can I get help on the Math ... 20 MOA

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Motorhead

Motorhead

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Nov 1, 2018
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I am needing to modify or fabricate new, a mount base for one of my slug shooters with a fairly high scope position.

* Whats needed is the how many .000" of an inch in height differential per foot or by the lineal inch equates to 20 MOA ?

** If it helps .. the base is 4 1/2" long, so how much wedge over that distance ?

Sorry to ask, but have not found the base anwser, only the math of which is not my strong suit.

Thanks !!
 
Scott, I'm not sure if this translates to anything helpful, but in shimming rear scope rings for more elevation, I believe I found it's about one MOA per .001" of increased rear ring height. I remember that .020" was my personal limit, just to avoid additional scope stress in mounting, and I believe that gave me about 20 MOA. We need a trig scholar.
 
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One MOA is 1.04" at 300 feet.

1.04/300=0.0034666..." per foot

That works out to
0.0034666/12=0.0002888 per inch

Times 4.5 is about 0.0012999 inch's of rise per MOA.

20 * 0.0012999 is
0.0259 total inch's of rise for 20 MOA on a distance of 4.5 inchs.
 
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OldSpook said:
One MOA is 1.04" at 300 feet.

1.04/300=0.0034666..." per foot

That works out to
0.0034666/12=0.0002888 per inch

Times 4.5 is about 0.0012999 inch's of rise per MOA.

20 * 0.0012999 is
0.0259 total inch's of rise.
Click to expand...
So if reading correctly, for a mount base of 4 1/2" IN LENGTH. the height differential "end to end" is roughly .026"
 
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Privateer said:
Wow Scott! I'm surprised you didn't ask rsterne. Then again he blows my mind on simple questions.
;)
And what you working on that needs that 20 MOA lift?
Click to expand...
Finishing touches on my Retrofitted to balanced valve THEOBEN MFR .177 .... It is running @ 28 fpe and is now hopefully my small bore Ice pick.
Changed mount from whats shown & have a 2.7" scope height, thus requirement for the rail angle correction.

Picture #2 with current mount to be used.
y.jpg
 

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Quick question Scott: why 20 MOA? Since you are doing the machining you can decide on whatever, why not go a little more since you are going long range?


Which scope and with how much internal elevation and are you planning on dialing or hold over? How much elevation or how far are you planning on shooting! Ideally you want to zero close to lowest elevation adjustment so you can get max up adjustment/travel for longer shots.


Or are you only interested in canceling out the mount height so you are optically center at zero.
 
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qball said:
Quick question Scott: why 20 MOA? Since you are doing the machining you can decide on whatever, why not go a little more since you are going long range?


Which scope and with how much internal elevation and are you planning on dialing or hold over? How much elevation or how far are you planning on shooting! Ideally you want to zero close to lowest elevation adjustment so you can get max up adjustment/travel for longer shots.


Or are you only interested in canceling out the mount height so you are optically center at zero.
Click to expand...
The latter .... 150 ish yard max with .177 slugs. just need a clear FOV with having scope near optical center at @ 35 yards.
 
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