Scope Newb here....

[TexasAggie]

I just bought a Tikka T3 Tactical in .308 used. The owner of the rifle from whom I bought mounted a Leupold Mark 4 4.5-14x50mm M1 with the mil-dot reticle on it. I think I understand how to use the mil-dot as a means to gauge distance. I also understand how to use the mil-dots as a means to determine the mils for a given target. What I don't understand is the following:

If I know my target's distance and I also know the mils of the target, where do I aim the scope? Meaning, I'm going to align the vertical cross hair on the target, but by which mil-dot will I allign the target? Is this something that I need to determine by just going to the range and shooting the weapon at 100yds/200 yds/300 yds/etc?

It's probably a ridiculous question, and I've looked all over for answers; hence, I come to the experts at Calguns for a little guidance for this scope newb. Any help is much appreciated!

TexasAggie

[Stringer]

If I know my target's distance and I also know the mils of the target, where do I aim the scope? Meaning, I'm going to align the vertical cross hair on the target, but by which mil-dot will I allign the target? Is this something that I need to determine by just going to the range and shooting the weapon at 100yds/200 yds/300 yds/etc?

Mil or MOA marks are for determining the distance of a target given a target's size.

Once you've determined distance, you can calculate the bullet drop over that distance in inches or cm, provided you know load's dope. Yep, for that you'll need to go to the range.

From there, some people may try to holdover, as you describe (not using the "crosshair") to compensate for bullet drop, but many folks will twist the elevation turret the appropriate mils or MOA and aim with the "crosshair."

If I was you, I'd get a duplex or German #4 reticule. Clean and practical. No one mils targets at the range anyways. Mils may be good for hunting, but if you know how to use your duplex subtensions, it's a moot point.

[TexasAggie]

Stringer, thanks for the response. How would I go about calculating the "holdover?" Take for example the following: I eye my target with the mils and determine that it is 450 yds away, and I know that my .308 ammo is going to drop about 16 inches at 450 yds. If MOA is equal to one inch at one hundred yards, ~2 inches at 200 yards, ~3 inches at 300 yards, and ~4.5 inches at 450 yards, I would adjust my elevation turret 18 (4.5 inches/.025)clicks high and just aim with the cross hairs?

Did I understand that correctly?


TexasAggie

[Stringer]

Conceptually I think you are correct, but I'm not totally following the math. Of course I might be doing it wrong myself

Let's see, if the drop is 16", then the drop in MOA is 16/4.5, which equals 3.55 MOA. If your scope has 1/8 MOA clicks, then you need 8*3.55 clicks (28 clicks) up. Hope that's right

What is being described here is how to do adjustments that get the crosshair at the point of impact, which isn't "holdover." You can holdover using mil or MOA type reticules easier than with a duplex, but it would be even better with a Horus reticule which seems custom made for this. Now if you have a mil-based reticule and a scope with MOA adjustments, the math gets tricky, because 1 mil is about 3.5 MOA, a pretty odd number. However, in the example you gave the math is real easy (again unless I'm doing this wrong). The shooter, opting not to twist knobs, would hold the crosshair 3.55 MOA over the target, which is about 1 mil, making the holdover easy (just aim with the first dot under the cross.)

[FLIGHT762]

Just remember, your Leupold is very likely a 2nd focal plane scope. Any calculations and holdovers have to be calculated/used at 14X.

A first focal plane scope can be used to calculate at any power since the reticle adjusts as you turn the power up or down.

Using a .308 168 BTHP @ 2700 FPS and using a 200 yd. zero, the trajectory drop will be about 8.13" at 300 yards. The #1 mil mark is 10.80". At 400 yards, the drop will be about 23.75". The #2 mil mark(2mils up) is about 28.80". At 500 yards, the drop will be about 48.05" the #3 mil (3 mils up) is 54.00". At 600 yards the drop will be 83.48" and the 4 mil mark is 86.40".

These are rough calculations and were used with a default of 2.5" sight height for a SR-25. You can use mils as rough estimate, but using the elevation turrets are much more accurate and doping the ranges with your ammo and rifle is the thing to do.

It does give some confidence to shoot at a 600 yard steel plate and get a first round hit using four mils, but using mils as a holdover is not precise.

If you want to use a mil dot scope, you need to sit down, understand the variables and go to a ballistic chart. Even with the best calculations on paper, shooting is the best way to get your dope. An example is at 600 yards, my calculation came to 62 clicks elevation. When firing though, the elevation came to 58 clicks. On a colder day, I might have needed 62.

[FLIGHT762]

Stringer, thanks for the response. How would I go about calculating the "holdover?" Take for example the following: I eye my target with the mils and determine that it is 450 yds away, and I know that my .308 ammo is going to drop about 16 inches at 450 yds. If MOA is equal to one inch at one hundred yards, ~2 inches at 200 yards, ~3 inches at 300 yards, and ~4.5 inches at 450 yards, I would adjust my elevation turret 18 (4.5 inches/.025)clicks high and just aim with the cross hairs?

Did I understand that correctly?


TexasAggie

The other thing you need to grasp is, if your scope has 1/4 min adjustments you need to understand this.
At 100 yards each click is 1/4". At 200 yards each click is 1/2". 300 yards each click is 3/4". At 400 yards, each click is 1" and so on. At 800 yards each click is 2". As range increases, you have to add 1/4min.(.25")

If your drop in inches is 28" at 400 yards, you would move your elevation turret 28 clicks(from a 100 yard zero). It comes down to mathematics.

When you go out and actually shoot the rifle at the various distances, you'll figure it out.

Having your recorded zeros in a dope book, you can refer to it. On my tactical team,I had my dope printed out on my rifle stock. I could confidently take torso shots out to 400 yards.

The most difficult calculation is doping the wind.

[TexasAggie]

Fantastic information, guys. I appreciate it. I can't pick up my Tikka until Tuesday. I'll take it out next weekend and see how it goes. I'll have more questions going forward. You've given me some good info to think about. I appreciate the help.

TexasAggie

[dk-1]

I'm a little late in this thread, but let me see if I can help out here.....

-Using the scope you mentioned (Lupy 4.5-14x50 M1 Mildot) Your knob "click" value is 1/4" per 100 yards. Leupold "MOA" is calculated in "Inch Per Hundred Yards" (IPHY). True MOA is 1.047" @ 100 yards. If you end up with another scope, double check the values. MOA and IPHY are both angles of measurement.

-Mildots are easy, they are another angle of measurement. To "Mil" your target for distance in yards: take the size of target in inches and multiply that by 27.778, then divide that value by the number of mils the target subtends in your reticle. Example, 18" target multiplied by 27.778 = 500.004 divided by 3.2 mils gives you 156.25125 yards.

-Chronograph your load, record the average atmospheric conditions in your area, know the Ballistic Coefficient (BC) of the bullet your using, then plug your info into a ballistic calculator (there are free calculators on the web).

-Confirm your dope with live fire at 100, 300, 600, 800, and 1000 yards. Three rounds at each distance should suffice.

-When you set up for a shot, range the distance first (either by milling it, LRF, or other method). Dial in the elevation dope, don't forget to calculate for atmospheric changes from your recorded dope data. Adjust for windage. Take your shot! If these steps are taken CORRECTLY you should make consistent first round hits.

--On to the mil/MOA conversions... One mil is equal to 3.438 MOA. If you want to calculate for mil holdovers on your reticle, divide your dope for a given distance by 3.438 and that will give you your mil holdover value. Example, if your zeroed at 100 yards and your dope for 400 yards in MOA is 7.9 MOA, your mil holdover will be 2.297 mils, but I would round that to 3 mils.

--I would forget about "CLICKS", you will just confuse yourself counting 1/4 IPHY/MOA clicks. Use the numbers indicating IPHY/MOA which are engraved on your knobs! Example: for a 400 yard shot requiring 7.9 MOA, round that to 8 MOA, crank your knob to the number "8" and your good. For a 250 yard shot requiring 3.3 MOA dial to "3" and add 1/4.

--Mils holds work great for wind corrections as well, as the wind may change frequently and you may need to constantly correct for this. I break it down into 1/2 MOA increments. 1/2 MOA is roughly .15 mils. I just compound that value as needed for any wind adjustments. Example: If I am in need of 2.5 MOA for a wind adjustment, I hold .75 mils.

I hope this helps and I hope it is all understandable!!!

[kato4moto]

I'd also suggest taking a precision rifle class. Pretty much any decent one will give you a basic understanding of using a mil-dot reticle correctly, plus you'll get instruction on correct shooting positions and other aspects of this fascinating and challenging part of the sport. And I'm sure you'll waste a lot less ammo than trying to learn on your own.

[TexasAggie]

Who do you recommend as far as classes go? There's one here in Bako, but it runs $800 for two days...I'd like to not have to spend that much...my hobby is getting a litte too expensive for my wife.

TexasAggie

[dk-1]

Spend time on www.snipershide.com and money on ammo. After a short time on the hide and about 1000 rounds down the tube, my 48 hour first rate LE sniper school seemed pretty elementary. Just my $0.2....