Yes, It is funny how that inversely proportional system works. I learned a lot about this some years ago right out the front window of my house actually. The street ran straight away from my window to over 1000 yds. distant. So i took a tape measure and a laser 1 day and measured and lasered all the signs. I wrote down those figures, and i then literally had an optics laboratory established right out the front window. I could then calculate X's i would need to bracket signs between plex post tips. It was really fun, and quite educational. One of the best things about understanding the "mod. mil-ranging formula" is that it allows u to calculate how effective the system is, and a couple other things as well, since it's composed of 5 different variables, any of which can be easily calculated once the other 4 are known. It's really simple mathematics. Here's a link to an article on the web that explains reticle zeroing, and rangefinding that may help. It also includes point blank range rangefinding and rangefinding with ballistic reticles under Item C) Reticle Rangefinding--
Nice thing about it is u can order the optics catalogs, from many of the companies that advertise their reticle subtensions. This has been extremely helpful for me, and really the best source of info regarding scopes.
Couple years ago i was out at a turkey shoot, and we had to shoot a bowling pin at 600 yds. I was using a 3-12X Burris LER Ballistic Plex reticle, that i'd measured the reticle subtension from upper post tip to axis @ 3.1 inch per hundred yds. Before we shot i asked if i could measure the bowling pin. It was 15" tall. When we got to the 600 yd. line i gapped it in my reticle at 0.8 of the abovementioned subtension. So by applying the "MMRF" above here it is--
15 x 100 / 3.1 / 0.8 = 605 yds.
Neat, i thought. Later as i got a better grip on the system i then realized just how lucky that was when i started manipulating the formula some.
1 last thing about this reticle-ranging stuff. I now have a Tactical Milling Reticle in a Leupold scope, that has a very fine system of ranging to the tune of .2 mil stadia. Most guys apply that reticle to an accuracy level of maybe 1/4th of that subtension, since it can get quite complicated trying to divide it into tenths, but once reticle subtension is understood, it can be very easily calculated if the basic ranging unit is .2 mil instead of the std. 1 mil. This stuff is an education, and a fun one for sure.