Reticle Range Estimating....

[Buttermilk]

Thanks to sscoyote, I think I have just about gotten a grasp of the reticle ranging using the subtension of the reticle to estimate range. At least I have a basic grasp of the math involved now... Using it in the field will be another matter...

Using my Burris 3x-12x AO Fine Plex here's what I come up with:

Using PPT to PPT
TrgtSz 15"
Power Range
3 69
3.5 81
4 93
4.5 104
5 116
5.5 127
6 139
6.5 150
7 162
7.5 174
8 185
8.5 197
9 208
9.5 220
10 231
10.5 243
11 255
11.5 266
12 278

Using Cross Hair to PPT
TrgtSz 15"
Power Range
3 139
3.5 162
4 185
4.5 208
5 231
5.5 255
6 278
6.5 301
7 324
7.5 347
8 370
8.5 394
9 417
9.5 440
10 463
10.5 486
11 509
11.5 532
12 556


Now, at least, I am starting to understand the "system" of using the reticle for range finding.

Now, I gotta practice....

Thanks, sscoyote.

Regards,

Rog

 

[sscoyote]

Rog, there is only 1 problem with the Burris systems. The magnifications and power rings don't match up perfectly. If u look at the Tech Specs pg. of their catalog it shows that @ 12x "dimension W" as they call it (plex post tip to plex post tip) is 5.4 inch per hundred yds. (IPHY), but at 3x it's 18". Since the system is inversely proportional it should be 21.6 IPHY at 3x (5.4 x power ratio of 4 = 21.6), so the proportionality is off somewhere along the power ring. I know some of the magnifications aren't exactly as advertised, and that's probably where the discrepancies are coming from--my guess at least. It's always a good idea to check the measurements as well, as 1 of my 3-12's Ball. Plex reticle is not as advertised between X-hair and PPT.

...but it's close, and will still work pretty well. Nikon's works perfectly according to the Tech Spec pg. in their catalog.

If u have a window that u can look out at some objects that u can measure and laser back to the window that provides for an excellent optical std./stds., of sorts to play with. Have a buddy that uses a stop sign that's 600-some yds. from his house that he uses. He's mill'd it and seems to have gotten real close as i remember. I highly suggest this system of practice as it's easy to do at your leisure. One idea is to reverse mill. with the reticle to see how close u can come to calc'ing the size of the object too. Stick with the mil-ranging formula as that is truly the best system to use, since it allows for the highest degree of accuracy and flexibility for reticle-ranging and reverse milling (calc'ing any 1 of the other 4 variables once range is known).

Remember the only problem with the system is that the tgt. size is not a constant anymore with game animals as they don't come in "1 size fits all." ...but it is better than guessing, and will flat amaze u at how accurate it can be quite often.

 

[Buttermilk]

Shortly after I posted, I realized that the lower power was not jiving with the lower power spec. A quick glance thru my 2008 Burris catalog didn't reveal the actual power of the scope (I suspected that's where the discrepency is...). I didn't have time to comment on that til now. Have had a busy weekend of ATV racing with my son, and helping a daughter move...

Thanks for your input sscoyote.

Regards,


Rog