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Retreever
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MVA Silhouette Rear Scope Mount
Jun 12th, 2023 at 3:01pm
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Does anyone know how to interpret the vernier markings on this mount?

I have made the assumption that each increment on the mount body equals 1 MOA @ 100 yards so the mount has a total height capacity of 75 MOA - am I even close to being correct?

I have searched on line for instructions on how to use this mount and have not been able to find anything.

Help please! Tongue
Roger
  
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Cbashooter
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Re: MVA Silhouette Rear Scope Mount
Reply #1 - Jun 12th, 2023 at 3:20pm
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On a standard spacing of 7.2" unertl style spacing. 002" moves POI 1" at 100 yards

What is your base spacing and distance between the vertical marks on the rear base? The math is pretty simple.
  
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Re: MVA Silhouette Rear Scope Mount
Reply #2 - Jun 12th, 2023 at 5:50pm
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The ticks on the side scale of those sights are 0.005".  To get down to 0.001" you need to use the tick marks on the top of the screw.   Those are 0.001" each. 

Chris.
  
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Re: MVA Silhouette Rear Scope Mount
Reply #3 - Jun 12th, 2023 at 5:53pm
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I should add that I use those mounts on a couple of rifles with 28" scopes and 17" base spacing which makes for easy math.  One minute is 0.005".

However I mostly use them on the MVA 23" scopes which gives you 0.003" per MOA at 10.34" base spacing.  Sort of a pain as you have to get good at quickly dividing by 3, but you'll have range from point blank to over 1000 yards.   

Chris.
  
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Re: MVA Silhouette Rear Scope Mount
Reply #4 - Jun 13th, 2023 at 10:03am
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Cbashooter wrote on Jun 12th, 2023 at 3:20pm:
On a standard spacing of 7.2" unertl style spacing. 002" moves POI 1" at 100 yards

What is your base spacing and distance between the vertical marks on the rear base? The math is pretty simple.


Base spacing is 7.2" (18" scope) , per Chris the spacing between the vertical marks on the adjustment stem is .001".

What's the formula for the math? I have done a lot of reading and all I have managed to do is confuse myself.  Cheesy

Thanks, Roger
  
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Re: MVA Silhouette Rear Scope Mount
Reply #5 - Jun 13th, 2023 at 10:06am
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gunlaker wrote on Jun 12th, 2023 at 5:53pm:
I should add that I use those mounts on a couple of rifles with 28" scopes and 17" base spacing which makes for easy math.  One minute is 0.005".

However I mostly use them on the MVA 23" scopes which gives you 0.003" per MOA at 10.34" base spacing.  Sort of a pain as you have to get good at quickly dividing by 3, but you'll have range from point blank to over 1000 yards.  

Chris.


Thanks Chris I am using 7.2" base spacing on an 18" scope - what's the math for this configuration using this scope base?

Roger
  
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Re: MVA Silhouette Rear Scope Mount
Reply #6 - Jun 13th, 2023 at 2:30pm
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Retreever wrote on Jun 13th, 2023 at 10:03am:
Cbashooter wrote on Jun 12th, 2023 at 3:20pm:
On a standard spacing of 7.2" unertl style spacing. 002" moves POI 1" at 100 yards

What is your base spacing and distance between the vertical marks on the rear base? The math is pretty simple.


Base spacing is 7.2" (18" scope) , per Chris the spacing between the vertical marks on the adjustment stem is .001".

What's the formula for the math? I have done a lot of reading and all I have managed to do is confuse myself.  Cheesy

Thanks, Roger



3600 inches in 100 yards.
divide 1(if you want 1" increments) by 3600 to get the ratio(.000278) 
multiple this(.000278) number by your base spacing. 
7.2 x .000278 = .002 etc..

  
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Re: MVA Silhouette Rear Scope Mount
Reply #7 - Jun 13th, 2023 at 5:33pm
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Attached is the elevation required to obtain 1 MOA based on scope base spacing listed on the left.

Modern vernier tang sights have 100 divisions per inch allowing you to measure 1/100 of an inch elevation or .01".

So a 17 inch spaced blocks means for every 1/100 inch tang adjustment or 1 increment you get .01\.005 = 2 MOA of elevation adjustment.

So a 10 inch spaced blocks means for every 1/100 inch tang adjustment or 1 increment you get .01\.0029 = 3.4 MOA of elevation adjustment.

So a 7 inch spaced blocks means for every 1/100 inch tang adjustment or 1 increment you get .01\.002 = 5 MOA of elevation adjustment.

So the greater your block spacing the finer you are able to adjust your POI.
« Last Edit: Jun 13th, 2023 at 6:12pm by Schuetzendave »  
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Re: MVA Silhouette Rear Scope Mount
Reply #8 - Jun 13th, 2023 at 7:56pm
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Retreever wrote on Jun 13th, 2023 at 10:06am:
gunlaker wrote on Jun 12th, 2023 at 5:53pm:
I should add that I use those mounts on a couple of rifles with 28" scopes and 17" base spacing which makes for easy math.  One minute is 0.005".

However I mostly use them on the MVA 23" scopes which gives you 0.003" per MOA at 10.34" base spacing.  Sort of a pain as you have to get good at quickly dividing by 3, but you'll have range from point blank to over 1000 yards.  

Chris.


Thanks Chris I am using 7.2" base spacing on an 18" scope - what's the math for this configuration using this scope base?

Roger


That will be about 0.002" per MOA.   So each line on the vertical stem is 0.005" so each of those will be about  2.5 minutes.  Each line on the top screw is 0.001" so each of those will be 1/2 minutes.

Chris.
   
  
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Re: MVA Silhouette Rear Scope Mount
Reply #9 - Jun 14th, 2023 at 12:04am
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But Chris the picture of his sight clearly indicates 100 increments per inch on his vernier scale which equals .01" per increment.

How do you determine the increment is .005 inches which is 200 divisions per inch?

« Last Edit: Jun 14th, 2023 at 5:25am by Schuetzendave »  
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Re: MVA Silhouette Rear Scope Mount
Reply #10 - Jun 14th, 2023 at 2:34am
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Schuetzendave wrote on Jun 14th, 2023 at 12:04am:
But Chris the picture of his sight clearly indicates 100 increments per inch on his vernier scale which equals .01" per increment.

How do you determine an increment is .005 inches which is 200 divisions per inch?



You should get there by using 25 hash marks on the vertical adjustment screw that has 40 threads per inch.

In theory that mount has 125 MOA adjustment with 17” spacing, or .625” of adjustment. I have never confirmed that.
  
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Re: MVA Silhouette Rear Scope Mount
Reply #11 - Jun 14th, 2023 at 8:54am
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Schuetzendave wrote on Jun 14th, 2023 at 12:04am:
But Chris the picture of his sight clearly indicates 100 increments per inch on his vernier scale which equals .01" per increment.

How do you determine the increment is .005 inches which is 200 divisions per inch?



Sorry Dave you are right.  The marks on the vernier scale are 0.01".   I was just referring to the ticks on the vertical staff but not accounting for the vernier Smiley.

Basically it reads the same as their vernier sights, which I think was the idea when they developed them.  The extra scale on the screw becomes necessary as they are usually mounted with a much shorter sight radius than MVA sights.   

Chris.

  
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Re: MVA Silhouette Rear Scope Mount
Reply #12 - Jun 14th, 2023 at 9:08am
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The chart from MVA is a good guideline. But having said that the best way to figure out what each mark means is to get on the range and start shooting. The moa elevation knob is a big help in adjusting for elevation, but the moa windage knob just gets in the way and every time you unlock the elevation lever you'll give yourself an unknown unintended windage adjustment.
I actually prefer the Schuetzen mount over the sillhouette mount.
And actually the #2 mount is a better set up for 7.2 inch spacing and 18 inch scope than either the sillhouette or schuetzen mount.
They are in the process of bringing out a ceclicked Unertl mount, and the DZ unertl mounts work very well with MVA scopes on a 7.2 spacing.
  
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Re: MVA Silhouette Rear Scope Mount
Reply #13 - Jun 16th, 2023 at 9:48am
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Thanks to all of you who contributed I have worked through and summarized as follows, please do not hesitate to comment if I have anything wrong.

Summary

Formula: 3600 inches in 100 yards. Divide 1 by 3600 to get the sight ratio = 0.000278, then multiply .000278 by your base spacing. 7.2 x .000278 = 0.002.

With a spacing of 7.2" between mounting blocks for an 18” scope 0.002" moves POI 1" at 100 yards.

The increment marks on the vernier scale are 0.010".   The increment marks on the top screw are 0.0010".

For an 18” scope with 7.2” spaced blocks every 0.010” tang adjustment or 1 increment you get .01\.002 = 5 MOA of elevation adjustment.
 
  
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Re: MVA Silhouette Rear Scope Mount
Reply #14 - Jun 21st, 2023 at 6:07pm
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Retreever, If you're planning on shooting long distance, you may find that the scope will bind in the front mount with a 7.2" hole spacing.
  
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