All the reticle subtensions are in the catalog guys, and yes, that reticle has rangefinding written all over it. The problem is the circles aren't really big enuf to range anything to intermediate ranges which is where IMO reticle-rangefinding has the most viability. If u're gonna try and do it way out there, then it will have the correct subtension--1.5 inch per hundred yds. (IPHY)inside diameter, and 2.0 outside.
Now the stadia subtensions between circles would work well, and there's a bunch of stadia points to choose from. How's about a 16" back to brisket buck deer (Leupold std. they use for their RES). Top of last dot to bottom of lower post is 5 IPHY. Now just apply the "modified mil-ranging" formula (MMRF), like this (inches to yds.)--
tgt. size (inches) x range of reticle subtension measurement (usually 100 yds.) / reticle subtension (inches) / quantity of "gap" tgt. occupies = range (yds.).
...looks complicated, super easy to apply. Filling in the variables using the 16" deer, and 5.0 IPHY "subtension unit"--
16 x 100 / 5.0 / 1.0 (deer fits 100% of the gap) = 320 yds.
recognizing that 320 is a constant, we can enter it into the calculator's memory to calculate the rest of the ranging chart as follows--
320 / 0.9 = 350
Now if the deer brackets right in the center of the circle when his brisket is level with the bottom post that would be right at the 4 IPHY subtension. If we divide 4 by 5 (our subtension unit) we get .8 which is the 400 yd. reading noted above. If he fits bottom of circle to lower post that's 3 IPHY. 3/5=.6 ==530 yds. So here's the deer ranging chart --
TLD (top lower dot) to PPT = 320
CLD (center lower dot) = 400
sweet huh??...assuming u've guessed tgt. size correctly, that is...
How about a pr. dog like Leupold uses for their ranging feature in the VH reticle. They use 7.3" tall for a pr. dog sitting on his haunches on top of his hole, or wherever he might wanna sit, i guess.
x-hair axis to bottom of 1st dot (our new subtension unit)= 3 IPHY, now plug the variables in again--
7.3 x 100 / 3.0 / 1.0 = 245 yds.
243.3 / 0.9 = 270
center of dot= 2 / 3 ==.67 (or about 360 yds.--243/.67=360--can u see it?)
...so here's the range chart for a pr. dog--
X-B1D (bottom 1st dot) = 240
etc. to as far as u wanna go.
Once the MMRF is studied and applied i think u'll find it's the quickest, most accurate, and most flexible (can be used with any reticle that has more than 1 stadia point, line, whatever in it, fixed power and variable) reticle rangefinding system there is.
Reticle-rangefinding (and downrange zeroing) is one of the reasons i always get the catalogs from the different optics companies. Many advertise their subtensions, but Nikon is 1 of the best for that.
Last edited by sscoyote; 11-29-2007 at 05:55 PM.