30 MOA rails

[grandslam 4]

What is the calculation for a 30 and 40 MOA rails , What is the height difference from front to back on 20 MOA , 7 in rail, Help I have lots of 0 MOA rails and want to make 30 and 40 rails out of them
Thanks for all the help email me at jlyons1@comcast.net

 

[GenePoole]

There are 60 minutes in 1 degree so 20 minutes is 20/60 or 1/3 of a degree. The rail forms a triangle with the action so for a 7 inch long rail the height difference will be: 7 inches * sine(0.33°) or about 0.0407 inches. For 30 MOA: 7 * sine (30/60) = 0.0611. for 40 MOA: 7*sine (40/60) = 0.0814.

 

[Fotheringill]

Not to muddy up the waters, but please be aware that the closer the rings are to one another on the rail, the more severe the vertical alignment will be.

 

[carlsbad]

Not to muddy up the waters, but please be aware that the closer the rings are to one another on the rail, the more severe the vertical alignment will be.

incorrect. The angle as calculated above is independent of the location of the rings, unless you are assuming the location of the rings is where the measurements are being taken. The calculation above assumed the measurements are 7" apart. --Jerry

 

[Ggmac]

Not to muddy up the waters, but please be aware that the closer the rings are to one another on the rail, the more severe the vertical alignment will be.

Not true . They would still be on the same plane .

 

[Fotheringill]

Please take a look at the profile of any 30 rail with a scope mounted and tell me that there is no difference in the POA the further back the front rings are mounted. The scope is pointed more upward than not. I may be wrong, or thick, but it sure appeared that way to me when I put on a new scope.

 

[tobnpr]

^^
Makes no difference as others stated. The angle between rings is constant regardless of ring spacing. The vertical difference varies depending on spacing of course- but the angle is the same no matter where they are placed.

 

[Dusty Stevens]

The angle doesnt change

 

[Evan]

Please take a look at the profile of any 30 rail with a scope mounted and tell me that there is no difference in the POA the further back the front rings are mounted. The scope is pointed more upward than not. I may be wrong, or thick, but it sure appeared that way to me when I put on a new scope.

What you're saying is true for Burris signature rings, but a 1 piece picatinny rail with ordinary rings has the same angle regardless of mount position.

 

[mr45man]

Take a piece of paper and ruler. Make a simple drawing Put about 6 rings on it.
That should un muddy the waters.

 

[Fotheringill]

What you're saying is true for Burris signature rings, but a 1 piece picatinny rail with ordinary rings has the same angle regardless of mount position.

You got me there. I have these rings mounted.

 

[carlsbad]

I hope my post above wasn't seen as impolite. We all make errors. --Jerry

 

[Fotheringill]

I have been in NY for 71 years. NOTHING on this board can be taken as impolite.
No problems.