#65561 - 03/02/10 07:30 AM
Re: Drop compensation??
[Re: rlb]
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TCTex.
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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
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#65712 - 03/04/10 02:19 PM
Re: Drop compensation??
[Re: TCTex.]
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sscoyote
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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
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#65715 - 03/04/10 04:45 PM
Re: Drop compensation??
[Re: sscoyote]
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TCTex.
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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!
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#65717 - 03/04/10 05:37 PM
Re: Drop compensation??
[Re: TCTex.]
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sscoyote
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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!!
Edited by sscoyote (03/04/10 05:46 PM)
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#65721 - 03/04/10 06:41 PM
Re: Drop compensation??
[Re: sscoyote]
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TCTex.
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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
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Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well armed lamb contesting the vote
Benjamin Franklin
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#65797 - 03/05/10 06:30 PM
Re: Drop compensation??
[Re: TCTex.]
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sscoyote
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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.
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#65799 - 03/05/10 06:58 PM
Re: Drop compensation??
[Re: sscoyote]
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Tigger
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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.
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??
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#65802 - 03/05/10 07:25 PM
Re: Drop compensation??
[Re: sscoyote]
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TCTex.
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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.
Yes I would... I have seen people try to "break down" a mill dot only to make fools of them selfs...
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Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well armed lamb contesting the vote
Benjamin Franklin
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#65804 - 03/05/10 07:31 PM
Re: Drop compensation??
[Re: sscoyote]
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sscoyote
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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.
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Steve
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