Home Forums Hunting & Shooting Hunting Optics Mils, turret twisting and MR shooting briefly explained

Questions keep coming up about MOA vs mil, how to use mils, Etc and I've been asked numerous times to explain. So here goes.


The first requirement is to have a system that is sound. Stock, bedding, mounts, rings, scope, and shooter. Start at the start you night say.... Stuff gets real easy real quick when all those dots are aligned and real hard real quick when they're not. Your looking for a sound platform that banks consistency, reliability and durability in your favor. I will take a bit and give an overview as without this the rest won't matter.

The biggest weak link is the shooter. Hunters as a whole do not know marksmanship any more. The ones that do shoot generally sit at a bench and punch holes in paper until they get that one magical half MOA group, and then go to the next load or rifle. Get off the bench. Go to an Applseed shoot and learn field positions. The only time a bench should be used is to find a load and zero. Every other round shod be shot from field positions.
You are going to have to shoot- there is no way around this if you want to be able to consistently hit in the field at distance.


The biggest equipment weak link is scopes. I harp on scopes because they constantly fail. Line up 10 shooters with good rifles and Swarovski, Zeiss, Leupold, etc. hunting scopes and on average more than half will have problems before they learn how to shoot at long range. I'm not talking about thousands of rounds, I'm talking very often less than a few hundred. Get a scope that is designed to be durable and reliable. No one would buy a hammer to build a house that might break after a hundred nails. Manufacturers build scopes based on the fact that must hunters don't actually shoot. Even high end scopes are not built to be used constantly and especially at long range. Just because it has an adjustable turret does not mean it is at all suitable for the task. You can not take a normal hunting scope throw turrets on it and expect it to hold zero, track correctly and function properly. Unfortunately the list of worthwhile scopes suitable for normal hunting rifles is short.

Nightforce NSX Compacts
SWFA SS
Leupold Mark 4 fixed powers
Leupold 6x42's
And the Bushnell LRHS has been doing well.


Yes there will be people screaming that their -insert favorite scope- is perfect and they haven't had a problem with it. Keep in mind that a sample of one is meaningless. Between work, competitions, hunting and friends I see HUNDREDS of different scopes get shot a year with tens of thousands of rounds put through them. Every scope gets tested. I will take a fixed 6 power Leupold over just about any $2,000 European scope made simply because it will stay zeroed longer.


Mounts and rings. Throw the windage adjustables in the trash. My preferance is a good picatinny 20moa base paired with good aluminum pic rings. Good DD rings and bases can be fine as well. Talley's are ok, however I have seen several broken sets.

Remember the goal here is to keep your scope zeroed.



Stock and bedding go hand in hand. Good synthetic all the way. Bedding needs to be right to hold the barreled action exactly in place. The goal is stability.



Notice I haven't mentioned barrels, triggers or accuracy. As long as system puts all its rounds into no bigger than a 1.5MOA dot at 100 yards you will not have a problem hitting thw vitals of big game to 600 or so. By that I mean 10-15 consecutive rounds. No, that's not great accuracy but a gun that puts all it's rounds into a 1.5in dot at 100 will murder every big game animal at 600 that you care to point at.

The point is that- is the accuracy of the gun, or lack thereof, is not what causes most misses at medium ranges.


Learning to shoot at mid range isn't the hardest part. Chasing down problems with scopes and equipment is the biggest time waster.

With that out if the way and with a suitable rifle and scope- mils.


First- mils are not metric. They are an angular measurement exactly like MOA. The base system for mils is 10 just like the metric system which is why it seems that way. In short a mil is 1/1,000ths of any distance. 1 mil equals 3.6 inches at 3,600 inches (100yards), and 36 inches at 36,000 inches (1,000 yards). I only say this to stop the metric vs American crap. It has nothing to do with it.


Learning to use mils is easy. It requires two things- stop thinking in inches and adjust what you see in the reticle to the turret. That's it.


Given a suitable rifle and scope- in this case it's an FN 308 and SWFA SS 3-9x42mm with Mil Quad reticle-




Mount and bore sight.

Fire 1 round at 100 yards and observe where the impact was from center-





In this case the POA (point of aim) was the top right black dot and POI (point of impact) was right where the crosshairs in the spotter is. The spotter has a mil based reticle and this works exactly like using the reticle in the scope. Each tick is .2mils.

We read the reticle and see that the correction is- down .5mils and right 1.2mils to bring it to center. Dial that into the scope and fire 3 rounds.

POA is the top left black circle-




Here you can see the initial round and the following three after the adjustment-




Looking through the scope (or spotter) we see that POI was within the dot.

This is a known gun so I will only fire between 5 and ten rounds to ensure that it is zeroed.

In this case I fired 7 into the next dot down-




There is a 5-7mph right to left breeze which is good for around .1mil of drift so I leave it. It WILL be checked again in no wind to make sure that it is zeroed.


Slip the turrets to so the the "0" mark is lined up, note which revolution that both the elevation and windage are on and write it down-





Go to the long range to check drops. There is a white 12inch square on the right side at 440yards and the same on the left at 470 yards.

[img]http://i744.photobucket.com/albums/xx87/Vereor1/Mobile%20Uploads/image_zps2d21aeb2.jpg[/img]

Thanks for taking the time to post this. Posts like this make it worth weeding through all the drama queen posts on here.

I haven't chronoed this lot of ammo (175gr SMK's) out of this gun so I take an educated guess and input all the variables into the ballistics program, in this case- Shooter.












It gives the solution for the 440yard target-






Adjust the turret- up 2.5mils and I hold right .2 for the 2-4mph of R-to-L wind



and fire a round.

Look through the scope or spotter and as you can see it's .2 or .3 low and .1 left of center. Fire 1 more round to confirm and it is low as well-





Go to the program and change the velocity to 2,650fps which requires 2.8mils.




Put that on the gun and fire two more rounds and they are .3 or so high and .1-2 left-


[img]http://i744.photobucket.com/albums/xx87/Vereor1/Mobile%20Uploads/image_zpse902af2f.jpg[/img]



Change the velocity to 2,700fps for 2.6mil of elevation-
[img]http://i744.photobucket.com/albums/xx87/Vereor1/Mobile%20Uploads/image_zpsbb136ede.jpg[/img]


[img]http://i744.photobucket.com/albums/xx87/Vereor1/Mobile%20Uploads/image_zps071c781d.jpg[/img]



And fire two more. The first is nearly center and the second is .3 right hit as the wind died.

[img]http://i744.photobucket.com/albums/xx87/Vereor1/Mobile%20Uploads/image_zpsa5f3b982.jpg[/img]

I realize you said in short, but that's not quite true if the POI needs to move in a vertical plane that is normal to the line of sight.

I agree the deviation doesn't show up until more than a usual number of mils get involved.

Very nice work. Looking forward to the rest of the lesson. Thanks for taking the time to do it.

Call it good and move to the 470 yard plate-


Put that into Shooter and it gives me 2.9 mils-





Fire two rounds-





And go to the 680 yards 12 inch plate. Put it into Shooter and it gives 5.5mils of elevation.



Put that in the gun and go 3 for 4 as the wind is fish-tailing that direction.






Now the gun is zeroed, I have pretty solid data to start with and can now gun all those plates in practice further confirming the data. After making sure the data is good I print it out or write it down in 50 or 100 yard increments and tape it to the gun. I used to also play with the zero range and see if there was a decent way to make the reticle into a BDC. With the above load if I dial .3 up then my holds look like this-

300yds- 1 mil
400yds- 2 mil
500 yds- 3 mil
600yds- 4 mil


All the benefits of a BDC reticle and non of the drawbacks.




Now why a mil reticle (or MOA) over a plain duplex? BIG reasons! Princaply wind.


Every mil reticle is going to be broken down in either full 1 mil dots or hashes like the standard mildot, or feature hashes or marks every .5 mils, or go crazy like a Horus and have graduations every .2 mils. Now it should go without saying that the finer the reticle is marked- i.e. .5 mil, .2mil, etc, the more precise you can be with holds and corrections. The standard mil dot is perfectly adequate for what we want and has the benefit of looking very much like a duplex if that's easier for you.

The Mil Quad that this scope has, and which I prefer is broken down into .5 mils. There is a small mark every .5 mil and a large one every whole mil. It doesn't really matter what the graduations are in your reticle as long as you know what they are.


Mainly this is used for holding wind and making corrections. If a particular shot calls for 2.9mils of elevation and 1 mil of wind, then you just dial (or hold) up 1 mil and slide the horizontal crosshair into the wind to the 1 mil mark.




For any holds in between marks you just eyeball it. Break the reticle down into 10ths in your mind and hold where appropriate. This may seem complicated but it is very easy and quick. I have had no problems with people being able to pick this up. From 6 year old girls to almost 90 year old WWII vets.




To address those that will say the NDC reticles are faster... No. They are not. Faster to shoot? Maybe. Faster to hit? No.

Take ten shooters that are equally adept at dialing and holding, line them up and have them shoot 6-12 inch plates at odd yardages from uncomfortable and often unstable field positions on a shot timer and dialing is both faster and results in more hits.



Typing this on my phone and I'm sure I've missed something but hope it answers some questions.

Understand, however that will only confuse people. It's shooting not a math problem.

Good stuff Formid, just what I was looking for. So basically, you're zeroing at 100 yards and then fudging the numbers on the ballistics program until you find a dope that puts you on target at a couple of other ranges? At that point you've got all the data that you need to create a chart of 50-100 yard intervals, all of which will be confirmed by further shooting?

form thanks for the pictures and explanation. most of it I agree with but would add this. I think the hunting scope companies you mention make great scopes as long as you set them and forget them. no cranking. your suggestion on cranking scopes is pretty solid. I noticed you left out vortex. I would have too.

I like to validate the loads I shoot at 600, 800, 1000 measure actual, then use my applied ballistics app calibration. to adjust the program for actual drop. The last gun I used for this it added about 20 fps to my load.

Yep. Not the most precise way to go about it, but with a known BC, and the 175gr SMK is probably the most tested bullet in history, and a scope that adjusts correctly you can backwards calc it out on the program. A better way to do it however is to check it just before it goes transonic (about 800 yards with the above combo) and backwards calc the muzzle velocity.

It's a good idea to confirm this by measuring turret adjustment increments before doing the above procedure.

Tag; good scoop. Thanks for taking the time to post this.

Which torque wrench is that in the pic?

Screw the metric system.

Formidilosus,

Good thread. How about another on evaluating wind and determining wind values?

Thanks,

John

Exactly..
I was thinking the same as I read the above..

Warn I believe.









It takes me forever to type these out! grin.... Times limited the next few weeks but I'll try. Specific questions?

This is the only thing that I would disagree with. The Radian actually is part of the metric system, but I'm not sure why that's a bad thing?? The radian has been classified as the SI-derived standard unit of angular measure. However like most things metric, and as you've pointed out, it's actually easier to think in terms of base 10 units than others. As you know, a milliradian (a Mil) is simply 1/1000th of a radian. If we approximate for the purposes of shooting, a radian is roughly as high as it is far. So 1000 meters tall at 1000 meters distance. One milliradian simply means that the height is divided by 1000 at that distance, so 1 meter tall at 1000 meters distance. Or 10 cm (1 decimeter) at 100 meters (10,000 cm). The common click increment of 0.1 Mil would be equal to 1 cm at 100 meters or 2 cm at 200 meters, 3 cm at 300 meters, etc.

It's very simple to think in terms of base 10 units compared to 1/4's or 1/3's. It's easier to think and remember a correction of 5.1 Mil than it is to remember 17.21 MOA (or 17.25 to round to the nearest 1/4 MOA). It sounds elementary, but the reality is that it's easier for your brain to remember 2 digits instead of 4. Especially when you're trying to familiarize yourself with 5 or 6 drop values for a given load at various distances.