Help with Mil-dot reticle

B

Black Jack

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Hello guys, I hope somebody can help me with this. I have a remington Model 700 in .308 win. with a 26" barrel. I reload 168gr HPBT with 39gr of IMR H4895. I do not own a chrono so i don't know the exact velocity of my bullets but according to a few books i would say it's between 2400 to 2500 fps. I use a Bushnell 4200 6x24x40 scope for it. This combination has given me good success up to now. The rifle is zeroed for 100yds. I've tried to understand how Mil-dot works and stuff and i think i have a better idea now but i'm still wondering about something. How can you calculate what is the zero of my second dot, third, fourth, going down below the crosshairs? Most of the time I was hunting, I would not have the time to dial in with the scope even if I have the numbers taped to my scope. I would like to know what other specs i would need to be able to know the zero of the other dots or if i actually have to shoot it out. The reason I would like to know this would be when i'm covering an area that the game can come out from 100yds to 500yds. Being zeroed to 100yds or 200yds and you already know the general distance of different spots on the ground, you could make the correction with the mildots instead of dialing the shot for 550yds. I've seen that sometimes you don't have 5 seconds to make a shot on a trophy animal so having the time to dial it in with your range card is out of the question. I'm not sure i gave all the necessary info to get these numbers but I hope it helps. Thanks :)
 
Most of that comes with range cards and keeping track of bullet drop though practice firing.

And as for ballistic data, you really need your velocity to be able to get accurate data through a calculator..

so basically, you either need to be keeping careful track of your target shooting and testing out the drop with holdover and make a record of it or buy or borrow a chrony and get some estimate data through the computer

To effectively find out drop it simply takes lots of range time.

There is some computer ballistic programs though that will give you a good estimate that you can start from, but again, you need velocity
 
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Buy a rangefinder. If you're as retarded at math as I am, the ancient art of mil-dot ranging is imprecise, and by the time I have actually made the calculation, the critter has finished mating, gestated and given birth.

Seriously, a range finder and a ballistics chart made from the specifics of your own rounds take away all the guess work.... ie:

biggameinfo.com/BalCalc.aspx
 
Obtunded said:
Buy a rangefinder. If you're as retarded at math as I am, the ancient art of mil-dot ranging is imprecise, and by the time I have actually made the calculation, the critter has finished mating, gestated and given birth.
Seriously, a range finder and a ballistics chart made from the specifics of your own rounds take away all the guess work.... ie:

biggameinfo.com/BalCalc.aspx
Click to expand...

Now you have 2 to shoot at.:D
 
At 12X, the mil dots will be spaced 3.6mins apart center to center. At 24X, 1.8mins. At 6X 7.2mins. You should verify on paper/tape measure just to be sure.

When you get your velocity and generate a drop chart, it will tell you how many mins of up you need from a chosen zero. So if your drop chart indicates that you need 3.5mins of up to your desired distance, and you have your scope on 12X, put the first dot on the target and let fly.

That is the simple stuff, now the work truly begins. To hit game at those ranges, you need to know that your load WILL do what you want. That takes shooting and practise to make the hit.

Sighting in at 100yds, then depending on gear/charts for further is the best way for failure.

You have to verify that the chart, load, rangefinder and you are working in unison. Alot of loads and some rifles just don't have the mechanical accuracy as distances stretch out.

www.longrangehunting.com. Look at the articles on the left margin and you will find one that I have written to help shooters set up their scope for LR hunting.

When you have practised enough, dialing up to engage game at extended distance only takes a few seconds. Is way more precise and if you don't have those few seconds, maybe the game is already on the run and then, is that a viable shot that far away?

Jerry
 
Mildots are spaced apart as Jerry explained, they don't really make 2nd, 3rd etc zero's on you scope. They are a way to estimate range and holdover. JBM ballistics has a calculator (free) online that input your bullet, velocity, zero and anything else you'd like basically. It calculate bullet drop and target lead in inches, mils, moa or cm out to what ever distance you specify. great program to play with. - also lets you print range cards that show that info in a nice, concise format

Link: ht tp://www.eskimo.com/~jbm/

if you are more into just using the mildots to range with I can email an excel file or pdf of its output. Its a chart that has target size in mils on one axis and target size in inches on the other. Match the 2 up and it gives you a range (ie a 24" tall target is 2.0 mils high so it is 333 yards away) Check you range card from JBM for holdover (24.5inches or about 2 mils) and BANG.....FLOP


edit: read your article on the mile .223 shooting Jerry.... that is some dang fine shooting!
 
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X2 on Obtunded.............. or............. Put THAT scope on the Exchange and get the newer tactical one with the side adjustment, better knobs and faster changes for elevation.
6-24X50

M.
 
As said above, you don't necessarily need to know your velocity, but you do need to shoot at various ranges and record your actual bullet drop. You could then use a ballistics program to fill in the holes.

Most variable powder mildot scopes should only be used for range estimation and hold off set at the highest magnification. The basic formula requires that you know how tall or wide your target is in yards or meters, multiply that by 1000 and divide by the number of mils it takes to bracket your target, the answer will be the range in yards or meters depending on which you measured your target size with. My preference is to use inches. To calculate range for a target measured in inches, take the target size in inches and multiply by 27.778 then divide by the number of mils. You need to be able to estimate the space from the center of one dot to another into 10ths, some people use 8ths.

As an example, lets assume your target is 48" tall, and in your scope it measures 1.3 mils in height. 48" x 27.778 = 1333.34 1333.34/1.3 = 1026 yards.

As said above, if you have estimated the range and know your drop, you can make an accurate shot by holding off for the range with the mildots, the space from center to center of each mildot being roughly 3.5 MOA. If you have to hold over 7 MOA, you would hold 2 mils high. The same applies to hold offs for wind. A 10 mph cross wind would require a correction of 3.3 MOA at 500 yards, so a hold off of 1 mil would work.
 
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Thanks guys, and that's what i was looking for Jerry. I tested my rifle up to 300yds because i don't have a longer range at this point. I know that it drops 4" to 200yds and about 7" at 300yds. I just wanted to know something to start with. I mostly keep my scope at 12x when hunting. In Ontario a lot of times you can just be along the Hydro lines and watching if a moose or whatever will cross. Ranges in these spots are way farther than 500yds but i wouldn't shoot it anyways. Last spot i was i estimated the range at over 1000yds of what i could see but never dare make a shot like that. But they could still pop up just below the hill i was on, or way out there in the dip. I was always wondering if we could use the dots as others zeros because a moose trotting along will cover this opening in less than 10 seconds. Now many other factors come into play for the longer shots, but if it was at 300yds at a trot. Time would be running fast anyways. I will have to extend my range and learn what is the "come up" I'll need for farther out. Up to now, I never shot an animal that I didn't recover and will try my best to keep it that way. Thanks again.

PS. Just read the article u are talking about Jerry. Wow, got to try that for sure :)
 
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BJ, your hunting style is near identical to mine. You post over an open area with various shooting lanes and ranges. Animals usually pop out near the edges of cover at first light or just before dark.

Some tips you can use if hunting in a favorite spot. First off, mark landmarks. Boulders, stumps, anything that will be visible through your hunting season. Should of course be near your animal crossings.

Now build a map of your area with those landmarks and practise shooting and hitting those land marks during the spring and summer. Pick them at random and send a few rds at them to confirm that what you think will happen WILL.

That will also give you a chance to know which dot to use or how many clicks to dial up. When you are practised, it takes just a second or two to dial up which I consider a much better way to connect at longer distances.

Once you have reference landmarks, distance no longer becomes an unknown. You should also consider flagging the areas so you can see that the winds are doing. A slow 308 is not a wind cheater. I use a 7RM going fast and it helps in that department alot.

with practise, you will build confidence in what you need to make your shot. Maybe you need to build a rest. maybe cut down a few saplings to get a clearer shooting lane. Anything to help you KNOW where that bullet is going to go.

LR hunting doesn't allow for sighters!

if you are moving through various areas, you need to get a rangefinder. There is simply no way reticle subtension is going to work. IF you don't have the time to dial up a few scope clicks, you sure don't have to time to do the math to calculate.

if you hunt with a partner, let him do the ranging while you get your rest and rifle set. He spots to ensure it is legal and ranges, by then you should be loaded and set to fire. With the range call, you dial up your scope, aim/dope/fire.

Should be able to engage and fire well within 20 secs. If the animal is far away and you don't have that much time, let it run.

Jerry
 
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