Putting mil rad marks on reticle

[davewilson]

My plan is to have dots put in my scope for the different yardages below the center crosshair. i can determine how far apart they will be in MOA. but i'd like to put some mil rads above center to have a backup ranging system. how far apart are these things in terms of MOA? have to confess i know nothing about mils.

 

[jwp475]

1 Mill at 100 yard substends 3.6" which is 3.348 MOA

 

[davewilson]

JWP, thank you very much, exactly what i needed.

 

[dmgreene]

Dave why are you going to go with mildots for ranging? If you are going to use the dots only for range estimation, MOA dots would be a lot easier to do the math and dots set up in IPHY would be even easier to do than MOA.

David

 

[davewilson]

[QUOTE=dmgreene; If you are going to use the dots only for range estimation, MOA dots would be a lot easier to do the math and dots set up in IPHY would be even easier to do than MOA.

can you explain how to use moa and IPHY dots to range with and why IPHY is easier. i was looking mil rad and using a chart like Darrel Holland has on his reticle.

 

[davewilson]

am i right in assuming if i have IPHY dots and a 24"(assumed height) elk spaced exactly 3 dots, then the elk would be 800 yards?

 

[dmgreene]

Dave lets say you have a target that is 16".

First MOA
You range the target and it is 4 moa. The math would be 16" divided by 4.188(the 4moa range reading x 1.047) equals 382 yards.
There is an easier way to do MOA. Since 1 moa is roughly 5 percent larger than 1 IPHY you can do the math like this: 16" divided by 4 = 400. Now subtract 5 yards for every 100 yards to make up for the extra 5 percent. So divide 400 by 100 which is 4. 4x5=20 So your finial range would be 400-20=380 yards. That is with in 2 yards of the correct reading and you can do this all in your head.

Now IPHY
To figure in IPHY all you have to do is divide the target size by you actual reading without having to worry about that extra 5 percent. You don't have to convert anything because you are working with inches with your target size and your ranging scale.

Examples: 16" target, range reading 4 IPHY (16 divided by 4) 400 yards
2 IPHY(16 divided by 2) 800 yards
3 IPHY(16 divided by 3) 533 yards

With 1 mil being 3.6" at 100 yards its hard to do the math in my head and a mil is very course. The TMR, MLR and GEN2 mil reticles are better with their 1/2 mil spacing. I have one Leupold with the TMR reticle that I set a ruler up at an exact 100 yards and then I dialed the scope down until the 1 mil spacing read 4". I made a non permanent mark on the power ring where this was at. Then I went fine tuned it by shooting a 650 yard target that was taking 10 moa of dial up with a 100 yard zero. I then dialed the scope back to zero and used the 2 1/2 mil mark for a hold over aiming point. Then I used the power ring to adjust the point of impact. When I got to the same point of impact as the 10 moa dial up, I made a permanent mark on the power ring. With the 1/2 mil spacing of TMR adjusted to read 2 moa I have basically got the same reticle as the Nightforce NP-R2.
If I were to build a scope it would definitely have IPHY adjustments and a IPHY reticle. It's just easier for my simple mind.
I hope this helps.

David

 

[dmgreene]

am i right in assuming if i have IPHY dots and a 24"(assumed height) elk spaced exactly 3 dots, then the elk would be 800 yards?

Dave you got this one in while I was writing my long winded reply. You are correct if the dots are spaced 1" apart at 100 yards. If you had a 2" spacing then the range would be 3(dots) x 2(inch spacing) = 6. So 24 divided by 6 would give you 4 for a range of 400 yards. See how simple this is.

David

 

[davewilson]

David, thank you for the explanation. i've never considered a range finding system on the recicle until recently, and my knowledge with them was dangerous at best. i basically understood the MOA but didn't like that little .047 convertion factor. quite a PITA. the mil rad is just too difficult and needs a chart. but for us redneck, USA guys that deal in inches, the IPHY is just slicker than snot on a doorknob! i totally agree with your above assesment that mil radians is the most difficult, MOA is easier, but the IPHY system is by far and away the easiest to use in the field.

 

[DogZilla]

FIRST... FINE PLEX CROSSHAIRS ARE MUCH BETTER THAN DOTS.. DOTS OBSCURE THINGS...ESPECIALLY AT LONG DISTANCES WHERE MIRAGE MAY
BE SERIOUS..

CONSIDER FINE CROSS HAIR MARKS...


NEXT.. THOSE MARKS ARE ONLY GOING TO BE ACCURATE WORKED UP
ON THE LOAD YOU USE TO DETERMINE THEIR FIXED SETTINGS, ONCE YOU
USE DIFFERENT AMMO, DIFFERENT LOT OF POWDER, ANYTHING DIFFERENT,
THEY ARE NOT GOING TO WORK EXCEPT TO SHOOT TO POINT FOR EACH DOT OR HAIR THEN RECORD ITS DISTANCE... NOT VERY EFFECTIVE...

ITS JUST MUCH SIMPLER TO MAKE A SCOPE TURRENT CLICK LIST AND USE AN ACCURATE RANGE FINDER..

THAT WAY AS YOUR LOADS CHANGE, AND YOU RESIGHT, YOU MAKE SLIGHT CORRECTIONS TO THE CLICK LIST..AND YOUR IN BUSINESS AGIAN... WITH
MARKS OR DOTS .. YOUR STUCK.. COURSE YOU COULD SPEND ALOT OF TIME , POWDER AND BULLETS MAKING A LOAD THAT HITS RIGHT ON THE DOTS...

BUT THEN IF THE PRARIE DOG MOVES 10 YARDS.. YOUR SCREWED...
gun)gun)gun)lightbulb

 

[davewilson]

Dog, i understand what you're saying, i just don't agree. i've hunted with dots and cranking the turrets. for a carry gun shooting modest distances, i prefer the dots/ multiple crosshairs. most scopes will hold zero, but most variable scopes don't track very well. dots are the winner. when time is a little tight, dots are also the winner. most turrets that crank, stick up off the scope more, catching on the scabbard or anything. another plus to dots with lower profile turrets. i use a rangefinder, but a backup system is a nice thing to have. as far as changing loads/bullets. you'd be surprized how close different bullet trajectories are. i've shot 150, 165, and 180's in my 06 with dots and it's almost right on for each. again, i'm talking about modest distances, out to 800. precise aiming point, i'll give you that one, but i don't find it difficult to compensate for. if you can't line up on a deer at 800 with a 1/4 min dot, then you need to change something. again, i'm not talking about shooting at a gopher head at a mile. this is a big game carry gun that will be hopefully shooting an elk this fall in Wyoming.
with all that said, i am torn between just putting a MOA system instead of specific dots for distances for many of the reasons you mentioned. i will be using a dot/crosshair system rather than cranking turrets though. i havn't "pulled the trigger" yet!

 

[jwp475]

IME using the reticule in Mills or MOA for hold points at distance is a rather accurate way to go. I took an Antelope at 777 useing the reticule and drilled it throught the shoulders

 

[Pdvdh]

Shot a caribou at 850 yds using mil-dot holdover. No problem.

I tend to doubt that you're going to be able to put enough custom dots on a wire crosshair to lay them on there at 1 moa intervals. The dots alone will be awfully closely spaced and the cost of laying that many dots on a wire reticle would - I believe - just about force you into an etched-lens reticle rather than a wire reticle such as those installed on the Sightron SIII scopes. Nightforce, IOR, and other etched lens reticles - there's just about no end to what can be etched onto a glass lens. Wire cross hairs - I think there are both technical, and cost related, issues with how far you can go.

You've caught my interest though. Please follow-up with where this effort ends. I'd like to know if it's techically feasible, and financially cost effective, to achieve your goal with an after-market reticle customization.

 

[sscoyote]

I also like to apply reticles for rangefinding. It sounds like what u r going to do is have a BDC reticle installed. If u go here-- www.ottllc.com/specialtypistols/sp20.pdf and reference Item C) Reticle Rangefinding, it defines the system used for any reticle-rangefinding. For your applications the part on ballistic reticle rangefinding is what u would need.

I also like to use the TMR for rangefinding. I use the .2 mil subtensions as the main ranging unit always at the optics highest power, since it gives me an accuracy level for interpolating between stadia of .02 mil (.072 inch per hundred yds.). The smaller the unit of subtension the more accurate reticle-rangefinding is.

I like the stuff that Dave has posted here. When i range using a reticle tho i want it to have the highest degree of accuracy (smallest subtension) i can get out of the reticle. IPHY system is great for intuitive ranging, but when i range i divide any unit of subtension i am using into tenths )sometimes i attempt 20ths of a unit interpolatively. So if i have a 16" target and it occupies 1.0 of a 2 IPHY subtension, that's 800 yds.--easy, but suppose the tgt. occupies 0.9 of a 2.0 IPHY unit. That's not any less difficult for me to calculate than a 1.4 mil-reading. I still have to apply the formula. I can't do it in my head, but i still want the most accurate system of reference possible, so i will interpolate to that level of accuracy. 16 x 100 / 2.0 / 0.9 = 889

IPHY, MOA, mil., ballistic reticle...whatever u're using for rangefinding u should still understand the basic angular formula so u can get the MOST out of it.