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California Precision Rifle Club California Precision Rifle Club Forum |
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#1
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Understanding MIL vs. MOA
Re-posting here because many precision rifle shooters probably don't read the riflemans forum:
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Last edited by ar15barrels; 04-27-2010 at 1:57 PM.. |
#2
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First, Having a calibrated reticle with known-marks is uber-important.
You can't consistently hold for elevation or wind if you don't have some sort of calibrated scale to work with. Matching the knobs to the reticle is the 2nd most important thing. If you fire a shot and you observe that the impact was 2marks low and 1mark right, you know that you can adjust or hold 2marks high and 1mark left and your next round will be a hit if the wind has not changed. If your knobs don't match you reticle, you have to do more calculations to figure out how many marks in the scope equate to how many clicks on the scope knob. The 3rd most important thing is being able to quickly range the distance to target. This requires you to know the size of the target. The more accurate your assessment of the target's actual size, the more accurate your range estimation will be. Here's my take on MIL vs. MOA reticles and knobs. I'm an MOA guy, so my overview may be biased, but I think that even the MIL guys will agree that overview is factually correct. The actual choice of either MIL or MOA is a ford vs chevy arguement. Both cars will get you to work every day and both measurement systems will get you hits when used properly. There are basically two camps supporting the two different systems. First, you have the MIL crowd. 1 MIL is 3.6" at 100yds and can easily be rounded to 3.5" for ease of calculations in your head. This rounding will create a 2.8% margin of error. The biggest thing the MIL crowd have going for them is the military's use of that system and all the development the supporting of MIL-specific tools, binoculars, scopes etc. The basic premise why you should get a MIL reticle is "because military/leo uses it". When used in a rangefinding role, the MIL system requires a more complicated calculation to figure out how far away a known-dimension target is located. The accuracy of the MIL system at rangefinding relies on the ability of the user to divide up the milradian markings as precisely as possible when measuring the angular size of a target. To reach 1/10MIL reading, you have to divide up the space between two dots into 10 segments and then approximate how many segments your target occupies. Try this: hold your thumb and first finger out in front of you like you are measuring something. Now look across the room and find something that fits say 1/3 or 2/3 of the distance between your thumb/finger. Do not adjust your fingers to fit the object. Now determine how many 1/10's of that space between thumb/finger does the object fill. Is it 2/10? Is it 3/10? Is it 4/10? That's what you need to determine when measuring the height to 1/10 of a MIL. Then, you have the MOA crowd. 1 MOA is 1.047" at 100yds and can easily be rounded to 1" for ease of calculations in your head. This rounding will create a 4.5% margin of error. The biggest thing the MOA crowd have going for them is the ingrained use of inches as a common measurement system. The basic premise why you should get an MOA reticle is "because everyone knows what an inch looks like". When used in a rangefinding role, the MOA system has a less complicated calculation to figure out how far away a known-dimension target is located. It's easier to calculate a distance in MOA without a calculator as there is no "27.7 MIL factor" in the formula. The MIL crowd will be quick to point out that for the best accuracy of measurements, you still need to use a calculator and they are correct, but for a really quick (no calculator) range calculation, the MOA formula is simpler. The accuracy of the MOA system at rangefinding relies on the finer resolution of MOA markings when measuring the angular size of a target. To reach a 1/4 MOA reading, you only have to divide up the space between two hash marks into 4 segments and then approximate how many segments your target occupies. Try this: hold your thumb and first finger out in front of you like you are measuring something. Now look across the room and find something that fits say 1/3 or 2/3 of the distance between your thumb/finger. Do not adjust your fingers to fit the object. Now determine how many 1/4's of that space between thumb/finger does the object fill. Is it 1/4? Is it 1/2? Is it 3/4? That's what you need to determine when measuring the height to 1/4 of an MOA. The adjustment of a single 1/10 MIL click is roughy 3/8" at 100yds so that's the intrinisic accuracy of the MIL system. The adjustment of a single 1/4 MOA click is roughy 1/4" at 100yds so that's the intrinisic accuracy of the MOA system. So, while MIL clicks are not as precise as MOA clicks, they also requires fewer clicks to adjust the scope from one elevation setting to another elevation setting. This is an important factor when you need to adjust the scope from your 100yd zero to another distance quickly. Let's say your bullet drops 54" from your 100yd zero to your 500yd zero. That would equate to 10.25 MOA or 3 MIL of adjustment. If you were to compare two nightforce scopes, the MOA knobs have 10 MOA of adjustment on one turn and the MIL knobs have 5 MIL of adjustment on one turn. So, you can see it's quicker to turn the MIL knob 2/3 of a turn than it is to turn the MOA knob 1 full turn plus another click. However, at 500yds, a single 1/4 MOA click equals 1.3" while a single 1/10 MIL click equals 1.8" so you can also see that the MOA system has 30% finer resolution when trying to dial-in your impact precisely. My summary in support of the MOA system is that you have a finer resolution to work with that's easier to use for rangefinding without a calculator, but fewer companies making scopes with MOA reticles. My summary in support of the MIL system is that you have quicker adjustments and more support in the variety of scope manufacturers and the wonderful "mil-dot master" sliderule that eliminates the need of a calculator to quickly estimate ranges.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#3
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Quote:
And now someone has moved it to the optics forum which even fewer people read before they choose a scope.
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Rob Thomas - Match Director NCPPRC Tactical Long Range Match Match Director Sac Valley Vintage Military Rifle Long Range Match |
#5
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__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#7
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Randall definetly knows his sh#@. He is so fluent in MOA and MIL he makes me feel stupid. I want a Vulcan mind meld!!!
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"I was that which others did not want to be. I went where others feared to go, and did what others failed to do..." |
#9
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Randall, can you explain how you made your moa reticle read in mils that one time at APS? Is it just a matter of making the hash marks equal to the amount of mils that one sees through a mil reticle when looking at a particular object?
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#10
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Quote:
Find two marks that are 6' apart at exactly 100yds. Dial the scope until it measures 10 hash marks. Make a note where the power ring goes to see exactly 10 marks spanning 6' at exactly 100yds. THAT power is your MIL setting.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#11
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Randall,
On my MLR reticle when figuring the "hash marks" should I use only the whole mil stadia marks?
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"I was that which others did not want to be. I went where others feared to go, and did what others failed to do..." |
#12
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This was when Randall wanted to use his NF MOA reticle to read MIL's.
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Luck favors the prepared. The original battle plan did not survive initial contact with the enemy. "The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt |
#13
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Quote:
If it's NOT reading 20 mils when you measure a 6ft long stick at 100yds, then it's not accurate.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. Last edited by ar15barrels; 07-01-2009 at 8:15 AM.. |
#15
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I have been meaning to draw this for a long time.
Some recent discussion and the stickying of this thread put me over the edge... MOA vs MIL visually:
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. Last edited by ar15barrels; 04-27-2010 at 2:02 PM.. |
#16
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What? I'm guessing you meant 10 MILS with a 3 FT stick (also commonly referred to as a yard stick ) at 100 YDS.
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#17
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Fixed.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#18
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that's it ! I'm going MIL plus I'm more familiar with meters as well...what is the main difference between the mil dot and MLR reticles from NF ?
also quick question but how much do you use the scope ranging system now that everybody is packing a Leica RF ? |
#19
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Quote:
http://www.nightforceoptics.com/RETI...t-15x_copy.pdf The MLR also has half-mil hash marks. http://www.nightforceoptics.com/RETI...L/MLR_copy.pdf Quote:
The main value in having a reticle with calibrated marks is to hold-off for wind or to hold over/under for shooting multiple distances without turning the elevation knob.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#21
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FFP lets you range at any power as it is accurate at all powers.
SFP is only accurate at one power, but SFP usually gives you a finer reticle at the power where the retiicle is calibrated. I have developed a system with the Nightforce NP-R1 that allows me to use it as a MOA reticle at 15x and as an MLR reticle at 8.1X
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#22
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Did you get your question answered?
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