I am working on ballistic tables for a 30-06 shooting a 150 projectile. I want to use my mil-dot as a “ballistic plex.” The only way I know how to do this is by set up targets at the actual intended ranges with corresponding drops. EG, have a box set up at 400 yards with blue tape indicating the proper drop and then view the target threw the scope and count the mil’s.

I plan on doing this out to 500 yards, but is there another way to figure out drop charts and mil dot placement.

Thanks in advance

Duanec

I've been using the JBM Trajectory Calulator lately and it is working great! You'll need to know you parameters (alt, temp, fps, bc, scope height, etc, etc)

Plug those in then run the calc's. You select how you want the data displayed...MOA, inches, mils. Run yours in mils and it will tell you what mils relate to yardage. Then go out and shoot to confirm the results.

JBM Calculator

Great link Dan, thanks.

Another good calculator is.....http://www.handloads.com/calc/
but, confirmation is still important.

Your 100% right... I would like to do it both ways. It also helps when you trying to shoot at an odd ball range. I would like to get several ranges confirmed manually AND try to figure out the trajectory threw math…

My goal is to be practicing this summer on armadillos!! (insert sinister laugh here)

Dan... I owe you one!!!!!

I started playing around with that sight and all I can say is that I am a sponge!

THANK YOU VERY MUCH!!!

If you're practicing in the heat of the summer just remember the load will more than likely shoot different in the hunting season so make sure you go back and check velocity on your load and make necessary corections on your chart. Especially if you are using a temp sensitive powder.

Just a thought.

No problem buddy. I did this with my .260R Striker then a 7mm RSAUM and 300 RUM rifle. After running the tables and zeroing at a known distance, I ran the dials to various ranges from 200 to 500yds and all three were DEAD ON!

I can't wait for about three FEET of snow to melt so I can stretch out my .308W Competitor and do some more work with JBM.

Thanks RLB, I haven't gotten that far... yet...

I got spoiled with my Wife's 30-06 and a Burris Ballistic-Plex. I am wanting to learn the Mil-Dot for both ballistic compensation and rangefinding!

Wow I feel like I just got my feet wet...

You're going to have to buy more barrels now so you can keep playing.

Ha Ha Ha Ha Ha...

I have a 270, 30-06 and a 7mm Rem Mag with Mil-Dots on them... The 270 wears a 6-24 X 44 Signature Burris B-Plex, the 06 wears a Nikon 4.5-14 X 40mm, and the 7mm wears a Ziess 6.5-20 X 50mm. I have been practicing rang finding with them for quite some time. Not bad at it, but I haven't done enough with them... I figure it is about I learned how to use the Mil dot for properly. LOL

IMO, reticle-rangefinding and downrange zeroing is the most fun shooting there is.

As it turns out it's all based on the most basic form of the mil-ranging formula (rangefinding and downrange zeroing)--Reticles/turrets, iron sights, whatever.

Here's the formula that i've memorized as all the simplifications and rearrangements of the mil-ranging formula are based on this 1, and this one's the easiest to manipulate for whatever u're doing with it (" to yds.)--

tgt. size (") x range of reticle subtension (usually 100 yds.) / reticle subtension (") / "mil-reading" (decimal equivalent) = range (yds.)

looks complicated but super simple to apply (only 5 variables). How about a 10" tgt. that occupies 2.5 mils. 1 mil=3.6 inches per 100 yds. Now just fill in the blanks--

10 x 100 / 3.6 / 2.5 = 111 yds.

If u think about it a bullet drop referenced through a reticle (or turret) is really the same sort of dimension as a tgt. size in this equation. So then how many MOA (1.047"=1 MOA) is there for compenstaing 52" of drop at 540 yds.? Same equation--

52 x 100 / 1.0472 / x = 540

x= 9.2 (go to the 9 mark on the turret and 1 more click).

Once a shooter understands this equation and the inversely proportional nature of magnification vs. reticle subtension in 2nd focal plane optics, things can be accomplished in the field that i never believed could be, honestly. Such as rangefinding to 1000 yds., calculating tgt. size at distance, etc. Here's more on the subject-- http://www.ottllc.com/specialtypistols/sp20.pdf Item C) Reticle Rangefinding

Mr. Steve... I remember your posts about using pistol scope as rangefinders... I have funny suspension that we are going to be having some pretty good conversations!

Hey TC--it's a kick, IMO. I think i like the math almost as much as the shooting itself.

Here's 1 of the discussions awhile back i just dug up--
http://www.handgunhunt.com/forum/ubbthre...=true#Post30492

Isn't it amazing to think that u can calculate the size of a target at 1000 yds. to that level of accuracy using a reticle subtension measured on another tgt. set at 500 yds.? Man, it sure is to me!!

Here's another example of how well it can work. I was out at a "sniper-style" match last year competing against some equipment that went way into the several thousand dollar figures. I was using this 4 MOA (windage) reticle here--



The shoot was 10 steel prairie dog tgts. set an unknow ranges to 425 yds. 1 shot each tgt. timed. Each tgt. had a Larue-style cardboard next to it to identify it. One of the tgts. was very difficult to get a laser reading off of--everybody was having a difficult time with it. But i thought that if i could reverse mil. the tgt. size from a tgt. that i already knew the range of and then mil the unknown range tgt. then i would have something to go off of. I can't remember what the dimensions/calcs. were now but it actually worked. I calcd. the tgt. at 300-something and hit it. That was 1 rewarding shot i tell u!

I was doing a lot of research on deer anatomy... Using the basic math... target (ears at 16in or chest at 18in) divided by mils X 27.75. It is kind of what you were describing. LOL I cut and pasted you info so I can make notes on it. The info on bullet ballistics intrigues me. I "want" to be able to figure both methods out and have them both pretty close. If I can do that I think I will be on the right path. Right know I can do the reverse math to figure out how many mills it should look like in the scope and come up with charts. I plan on going out with some cut outs to the Coast Guard base, where I have a 2200 yards strip range, and seeing what the look like. Not that I will be shooting that far, but...

I need to use Tig's idea and set up little deer and goats up in the leaving room and "practice" a little. He He He he

When i set up a reticle for rangefinding i use back to brisket measurements since that's the profile that is the least skewed and the easiest to see most of the time. A deer, coyote, whatever can't move his back up and down from his belly (very much), and so this measurement is basically constant. If it turns at a tangent the b-b profile is still seen, if it's standing in high grass it can also still be seen most of the time. Ernie (XPhunter) and i actually reticle-ranged a dead cow elk that was laying on it's side at 666 yds. and we came relatively close.

U would not believe the misiformation that is circulating regarding the concepts of reticle-rangefinding. It makes me laugh sometimes. Even the optics companies themselves screw it up--somehow.

Interestingly, there is a rangefinding-reticle out there that is based on a bucks antler width, can u believe it? It's the Bushnell DOA reticle. You're supposed to bracket the range stadia lines between his antlers to judge how far away he is or something like that. I mean how crazy is that to design a reticle mainly for that purpose. Guys like it though, and it sells. I often wonder though how many guys actually have used it for that purpose. That reticle actually replaced their 3 MOA Ballistic Reticle that was one of the best reticle concepts ever deigned, IMO. I never really saw one, but if the stadia were the correct subtension for thickness, a guy could hardly ask for more really--non-specific rangefinding, vertical and horizontal reference in 1 reticle designed around MOA--perfect, even runnig shot calcs if 1 were so inclined. I guess they didn't think so--oh well.

LOL.. I should not say this but the reason most guys like it is because they now have an excuse as to why the deer is so small when they actually get up to it after the shot.

Joe says, hey Ted you shot a bambi!!

Ted says, it looked alot bigger in the scope, I just don't understand??

Yes I would... I have seen people try to "break down" a mill dot only to make fools of them selfs...

Here's anpother exapmle of how it can wrok. That reticle above is on an AR-15 that i have set up for long-range shooting. I was hunting coyotes just this last week with it and had an encounter with a couple dogs that would not come into the call for love or dead cows. I snuck into a position that would allow me to ambush them when they were passing me using a dry reservoir dike as a shooting platform. I got into position and tried a shot but missed at long-range, and the dogs took off. One slowed down and started moving parallel to me. It would pass the far side of a small rise at long-range but i thought i could get a shot off from the top of it. So i ran over to it and got set up. Sure enuf the dog comes through a fence paralleling me. He was trotting quickly and i got the reticle on him and just for the heck of it thought to try and range him with it. I kept thinking .6, .6, .6. The problem was though i only had dope out to 440 yds. at .8 using 3.14 inch per hundred yds. subtension and 11" tgt. size. So i tried a hail mary shot and missed once again. I lasered it when i had a chance at 570 yds., and .6 calcs out at 583 yds. If i'd have had dope out that far, i would have at least come close to the range instead of just guessing. Facinating stuff really, IMO.

Good comments guys.

Steve and I have discussed the reticle range finding in person before and he is the one that tought me to use it. I have applied it to my Clearidge XP scope on the 243 Striker. It has a subtension of 2.48" at 100 yards on 20X. I usually use the head of the charlie as a target and they are about 4", the size of a softball. So if we use the formula with the head of the woodchuck taking up 2 subtension (distance between the dots) it works out like this;

4 X 100 / 2.48 / 2 = 80 yards away

If the charlies head takes up 1 mil it comes out that he is;

4 X 100 / 2.48 / 1 = 161 yards away

If the charlies head takes up half a mil it comes out that he is;

4 X 100 / 2.48 / .5 = 322 yards away

Sounds complicated but it's not. If you always use the same power and the quarry is constant, like hunting charlies all summer you can have the first part of the equation done and stored in your head or on a piece of paper and all that's left to do is divide the mils into it. For example I will find a charlie on a lower power and then dial the scope up to 20X, so I know that my 4" charlie head is going to be multiplied by 100 which is 400, then divide by 2.48 which is 161 and constant at 20X. Now just divide 161 by the mils his head takes up; example 1/3 or .33 mils is 488 yards. I find if you can break down a mil in 10th it mkaes the math easier. Don't forget your cell phone in your pocket has a calculator in it.

I have taken my range finder along before and checked this and I'm usually with in 20 yards of the reticle. Now a target that's 4" is tougher to determine the mils at longer ranges and a 15" deer, it will make it easier and a little more percise.

Steve if I made it sound to hard tell me.

Thanks for the Pm's Steve!!!

Have a buddy of mine that's killing coyotes waayy out there with an AR-10 243 this year. 1 of the best LR shooters i know (uses all the gizmos). The problem msot guys encounter is that when they use a ballistic-style reticle, if it doesn't add up to even hundred yd. intervals they don't bother to calculate with the in-between ranges. But that's IMPORTANT info to know. He's using a varmint hunters reticle in his Leupold scope, and has killed 4 of his LR shots using it, cause the coyotes all landed very close to his stadia points. A week agoi or so he had an opportunity at a 500-something that was in between the stadia points. His zeros were something like 470 and 535, and he couldn't figure out where 500 was or something like that. If the reticle doesn't profile out to even hundred yd. intervals, u still have to calculate those reference points. Suppose the 470 was 5 MOA, and the the 535 was 9 MOA. Now suppose the ballistics program called for 6.5 MOA. Now u have to start using the math. There are 4 MOA between the stadia, and 6.5 MOA is 1.5 more than the 5 MOA. Now if u divide 1.5 by 4 u get .4. That means if the 5 MOA mark is say the 3rd stadia the doep for 500 would be 3.4. See how that works? Do the same for windage and u've now created a sort of grid zeroing system for the reticle all in tenths (just like interpolating the mil-dot reticle), both vertically and horizontally. Here's a pic of 1 of my systems, ydg., then vertical, then windage, always in that order, no headers needed. It's not enuf to know where the stadia points hit u have to develop a system that's fine-tuned...unless they all fall on even hundred-yd. intervals. But u still should calc. windage, IMO.--



Here's rangefinding using the 1.8 IPHY (0.5 mil) for a coyote b-b (11") as my unit of subtension (100/1.8) for this reticle--

Oh my God--perfection absolute!!

Some guys can figure this stuff out in their head. It takes just the right sort. Tigger's one of them i guess...I'm envious!

Thatnks Steve... but I'm just an old country bumpkin...LOL Hey, remeber it was just 3 years ago this spring I came out and we each got a coyote?! Good Times!!

To add to the reticle ranging it's nice to be able to do this at different powers also. As you cange the power the mil subtension will change with 2nd focal plane scopes. The Clearidge scope I have is a second focal plane as most scope on the market are. If the company has a chart for thier scope mil values it's usually set for one power and not always you top power setting. Companies will highlight the power they give values for with the number on the power ring denoted by a different color or a circle around it. The Clearidge gives the values for three powers in thier specification chart. 6X, 14X and 20X, that makes it easier to calculate on different known setting in the power range. Here is a link to the specs page. Check it out.

6-20X Clearidge specs page

That's a good spec. pg. Dale. That's the reason i bought my 6-18x Nikon Buckmasters mil-dot, 'cause the reticle subtension is cald. for 12x and at 18 it's 66% smaller (i was actually concerned mostly with the dot as it's a prairie dog shooter and i wanted a dot that was smaller than the ~.75" dot std. for most mil-dots). I dial elevation with this rig and use the reticle for windage calcs. at 2.4 IPHY between dots. It's great system, IMO. Budy Mitch has made some 1st shot connections with the rig at close to 500 yds. in some wind--17 Fireball XP. 25 Horn HP @ 3400 mv.

IMO, once a shooter completely understands the ~inversely proportional nature of 2nd FP variable powered optics (subtension vs. magnification) and the "modified" mil-ranging formula, he's got a lot more going for him than most do.

You have me drooling...

Don't you guys know that if you talk/post to Steve in this way and encourage him to post this much about reticles, reticle rangefinding, etc... that he will not be able to sleep for a day or two and the convenience store clerks (or anyone who may mention numbers in his presence) won't know what to think when he begins to explain to the benefits of the inverse proportional nature of SFP's.

He may need to be hospitalized for reticle recovery therapy.
Is that a 12 Step Program?

Yes, and each Step subtends 1.047in @ 100 yards or .29089 Mil Radians...RIGHT?

You are right Ernie, I can see it now..........

Steve sitting in a folding chair in a circle of people in a half lit room, he starts by saying....

"Hello, my name is Steve and I suffer from constant reticle rangefinding and subtension proportions. I just CAN"T stop the math in my head.... did you know I can determin the size of you eyes from here with my modified pen and a slide rule??" LOL Just kidding Steve.

Steve I have the Nikon 6-18 also, great info on the 66% smaller at 18X. I think it will go on the 260 when I get it up and running. Have you done much with the Nikon yet?

LOL!

Never much cared for math beyond adding, subtracting, multiplying and dividing. Guess I'm doomed as to LR shooting.

I'm not that good at math-Just ask Steve and he will tell you

But there are a number of ways that you can get good info before you ever head into the field in knowing how to accurately reticle rangefind a object with your reticle or know the subtension of your reticle.
Still to this day, Steve can go over my head in a heartbeat with math.

I was going to say the only cure was to sell all of his "fancy" scopes and replacing them with stock 3-9 X 40's. LOL

Too funny boys- u know i'll know i'm in hell when i'm in the field with game all aroud me at long-range and when i put the optic to my eye it's a 6.5-20x Leupold...with a fine crosshair.

Or go to Sundance and see how the 'experts' do it.

Here's to it--see u guys there.

That's funny, that is the same scope I have on my 375 H&H rifle... a VXIII 6-20 50mm Long range target... (It was the best scope to put on my 375 at the time and it just stayed.)

I have a headache............

All is not lost.
You could still determine the subtension from the crosshair juncture to the outer edge....