Mil-Dot ????

[XBOW]

I just purchased a Nikon 4.5-14x40 mildot scope and Im trying to understand
milliradians. I do understand that from the center of a dot to the next center of a dot at 1000 yards is 1 yard. And is 3.6" at 100 yards. But this would have to be at a given magnification, Right? This scope has variable magnification, so how does this correspond? It really isnt necessary that I range from the mildots but I do find this fascinating.
Thanks in advance
Chris

 

[dig]

There is a ton of information out there on mil-dot, your specs are precise very close, just do a search on this site or google or youtube. As for are ranging (and sighting) unless its a first focal plane scope you are correct, the scope is normally set on the highest magnification to use MILS for this purpose. You can do a little math if set at half magnification say 7x in your case would be half, but again not extremely precise to rely on the adjustments. MOA adjustments are much simpler in my opinion but being a long time MIL user I stick with it.

 

[sscoyote]

Chris--yes, subtension is power specific with SFP reticles such as the one u have there. The Nikon MD's are cald. typically for 12 and at 14 it oughtta' be about 3.1 IPHY (12/14x3.6). I always use my optics at their highest power for downrange zeroing and rangefinding, so if i were RRF'ing with that optic i'd go straight to the slightly more accurate 3.1 inch per 100 yds. subtension (14x) and apply the formula-- tgt. size x range of subtension/subtension/mil-reading=range

I.E. say a 10" steel tgt. that occupies .75 of the dot to dot spacing @ 14x (3.1" per 100 yds.)--

10x100/3.1/.75=430 yds.

I also suggest searching here about RRF'ing (and Snipershide.com). Playing with the math is fun IMO also.

There is a lot of info out there regarding mil-dot RRF'ing but very little regarding the application of any multi-stadia point for RR'ing, which is way bigger (and more fun) than mil-dot math itself, IMO.

In fact if your into this stuff, as it turns out the mil-ranging formula not only defines RRing with any multi-stadia reticle, and turret, but also downrange zeroing.

 

[Greyfox]

As stated in prior posts, you scope is intended to be used at max magnification. You can go to several sites and and get all the specific details of the use of mill dots.

For someone who just wants a very quick and dirty reference you can use the following:

If you know the size of your target, example deer chest of 18" at the chest, multiply this by a standard factor of "27.8" which would be 500.4. Therefore, if the chest of the deer at 14x on your scope fit between the center of the two dots, or 1 mil, your deer would be 500 yards away. If it fit between 2 mils, it would be 250 yards, etc. If it was a coyote with a 9" chest, it would be 9x 27.8= 250 yards for 1 mil. It's quick and dirty. I will tape a little chart for my game for the mil yardages inside my scope cover. Windage adjustments are simple, 1 mil is approximately 3.5 MOA. If you set your scope at half the max power, 7x, you would use half the yardage. Example, your deer would be at 250 yards. This works well if you want lower power, closer range hunting and want to quickly determine range, or know if you shot is within the point blank distance of you load.
if have used this successfully when I can't get a reading in my RF in fog, etc. Can get you real close at the shorter ranges, like 500 or less for a deer. As stated, its quick and dirty, if your not well practiced in the use of mil dots. IMO.

 

[load]

I just purchased a Nikon 4.5-14x40 mildot scope and Im trying to understand
milliradians. I do understand that from the center of a dot to the next center of a dot at 1000 yards is 1 yard. And is 3.6" at 100 yards. But this would have to be at a given magnification, Right? This scope has variable magnification, so how does this correspond? It really isnt necessary that I range from the mildots but I do find this fascinating.
Thanks in advance
Chris

milspec is at 10 power
some are different

there is also usmc mill=3.48 moa and us army =3.6 moa

1 moa ia 1.04 inches at 100 yrds

 

[sp6x6]

It is handy to do a drop chart for you mil amd 1/2 mil then use reticle like a B AND C.With a 200 zero I get to 725 w/my mil dot on a 325 wsm.

 

[sscoyote]

According to pg. 55 of the '10 Nikon catalog the mil. in that optic is designed to mil. correctly at 12x (3.6 IPHY, and the dots are .2 mil) (as all Nikon MD's are) and at 14 it will be 3.12 IPHY. At 12x in that optic there should be gold lettering and a small hashmark above the 12 designation with the "mil" letters next to it.

Most companies are currently using the US Army round dot system at .2 mil. and 3.6 IPHY center of dot to center of next dot. The USMC version was 3.6 IPHY between like spots on oblong dots and each dot was .25 mil. designed to break the spacing down into 1/8th's (instead of tenths for the round dots). The round dot system is much easier to apply mathematically and just a bit more accurate.