Thursday, January 14, 2021

Redfield Accu-Range

 When I bought my Redfield 4x-12x40mm scope, they did not have a mildot reticle.  What I bought had the Accu-Range reticle which has holdover markers for various ranges out to 500 yards.

YouTube is awash in reviews of this scope, all about what you would expect for a reduced cost Leupold.

For some odd reason, Leupold does not list 5.56mm or 7.62mm NATO, only common hunting rounds, but I am assured that they are both Group 1 cartridges for the typical bullet weights.  This seems plausible to me, at least within the accuracy of most shooters (which is certainly the most that I can say for me).  

As nice as having holdover points for 300, 400, and 500 yards (you center at 200 yards), I wish that I could find MOA for the various parts (target circle, target radius, distances to 300, 400, and 500, and even the overall field for estimating longer than 500 yards).  Having an MOA for the target circle and radius would make it an effective range finder.  It appears from ballistics charts that there is a 3 MOA drop from center to the bottom of the target circle (the 300 yard holdover point), so the circle is 3 MOA, and the radius is 1.5 MOA.  I guess that I will need to go in the back yard and measure MOA for the whole field of view with a ruler.  

The 100 yard holdover (holdunder?) is 2/3 of the way from crosshairs to top of circle.  From 300 yards (bottom of circle to 400 point dot would be another 3 MOA.  From 400 yards (dot on bar below circle) to 500 yards (top of thick bar) would be another 3 MOA.

Winchester's ballistics app for 147 grain FMJ shows a 10 inch drop at 300 yards.

UPDATE: The Redfield 4-12x40mm field of view at 4x is 180 MOA.  Diameter/distance*57.296*60. Right?  No.  I keep measuring against objects of known diameter and distance and the results are absurd.   Yet 1 inch at 100 yards gives .955 MOA; the Moon is 2160 miles in diameter and 238,000 miles away Ann's that formula says 0.52 degrees of arc which is exactly right.   I am tired of trying to calculate from observed data and getting absurd results: a 17" wide object 25' away exactly fills the Redfield at 4x field of view which is 195 MOA.  Yet the math above puts the 500 yard holdover at 7.5 MOA from crosshairs and or is about 1/4th or 1/5th of the way from crosshairs to bottom of field which means about 75 MOA field of view.  I will settle with the numbers that fit with the dimensions for ballistics.

The 3-9x40mm Bushnell fine crosshairs seem to be 12.8 MOA from side to side.  That seems like a good fit for a deer,  belly to top at 200 yards, likely the primary use of this scope.  I think it is a first focal plane reticle; the width of objects across the reticle does not change 3x to 9x.  The Redfield is definitely first focal plane.

The 3x9-32mm Bushnell Sportview seems to be first focal plane reticle as well, and with identical MOA on the fine crosshairs,  again sensible for a deer rifle scope. 

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