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#16: Re: Minute of Angle - All you need to know. Author: slimjim, Location: Fort Worth TX

Posted: Wed Oct 06, 2010 3:27 am
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Dawgdad wrote:

I generally will shoot at 100-200-300-500 with one scope setting and play with the ballistics program BC values until they match my trajectory. Very few bullets match published values. Again really not a huge factor out to 600 but after that...

Dawgdad, isn't it better for VLD bullets if you figure out BC based on G7 vs G1?

Also, with an accurate enough rifle, I place the chrono at 250 or 300 yards and take the velocity readings at that range. I find it more accurate than trying to derive off trajectory drop and its easier to step-up than the tall vertical targets.

Last edited by slimjim on Thu Oct 07, 2010 10:51 pm; edited 1 time in total

#17: Re: Minute of Angle - All you need to know. Author: Dawgdad, Location: On the Prairie

Posted: Wed Oct 06, 2010 7:32 am
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yes to both

#18: Re: Minute of Angle - All you need to know. Author: metz3601,

Posted: Wed Oct 06, 2010 4:50 pm
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is there anything like the iSnipe program out there for a web OS phone??

#19: Re: Minute of Angle - All you need to know. Author: chambered221, Location: Lost for good !!!

Posted: Wed Oct 06, 2010 5:02 pm
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wtf

I now need a iPhone just to go shooting ............thanks for that bit of info !!! Bang Head

Good thread............I think !!! Shocked

#20: Re: Minute of Angle - All you need to know. Author: Suzanne, Location: Eugene, Oregon

Posted: Wed Oct 06, 2010 5:33 pm
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That's the most handy thing I've seen in those phones. I can't afford stuff like that, too many other payments to make. In my next life.......

Suz

#21: Re: Minute of Angle - All you need to know. Author: Pizzaguy, Location: Oklahoma

Posted: Fri Oct 08, 2010 11:39 am
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Mil-Dots….
Ok, let’s talk about the mil-dot scope for a little while. Mil-dots are a series of “known distance” dots up and across the cross hairs of a scope. The first thing everyone needs to know about mil-dots is that they are only a known distance on ONE power setting on a variable power scope. You’ll have to read the paperwork of your scope to see what power that may be. In most cases it is max power, but there are other types. Now there are scopes that the mil-dots are the known distance on all powers, this happens when the crosshairs are set in the first focal plane of the scope. You would be able to tell this because the crosshairs would grow and shrink when you change powers. For the sake of this discussion we are using a fixed 10X scope.

Typically a scope is five mils, mil-dots are really oval not round. One “dot” is really 1/4 mil. The distance between the top of one dot and the bottom of another is 3/4 mil and the distance between the center of a crosshair and the center of a “dot” (or the center of dot to center of dot) is 1 mil. (See picture) Ok big deal, what does that mean? What it means is that the mil-dots can be used like a ruler to measure the height of a target, or if the height of the target is known then the mil-dot reticle can be used to calculate the range of the target.

Mil-dots are 1 milliradian apart. A milliradian is an angular unit of measure. 1 milliradian = 1 yard at 1000 yards and 1 meter at 1000 meters. So with our fixed 10X scope, 1 mil = 3ft at 1000 yards, so a normal white tail deer that is 36” to the shoulder is 1 mil tall you can estimate that he is 1000 yards away right? Right. So if you know the height of the target in yards and multiply that by 1000 then divide by the size in mils = the range in yards.

Now 1 mil on a USMC scope is 3.438 MOA and on an Army scope it is 3.6 MOA so if you know which scope you have use that measure. But the standard, because most people don’t know which scope they have, is to use 3.5 and split the difference (And make the math easier). So we know, because we paid attention in the minute of angle section, that 1 minute = 1” @ 100 yards, 1 minute = 2” @ 200 years and so on, therefore 1 mil = 3.5” @ 100 yards, 1 mil = 7” @ 200 yards, 1 mil = 10.5” @ 300 yards and so on.

Don’t worry I will be bringing all of these sections together before I’m done

Last edited by Pizzaguy on Fri Oct 08, 2010 2:46 pm; edited 1 time in total

#22: Re: Minute of Angle - All you need to know. Author: Pizzaguy, Location: Oklahoma

Posted: Fri Oct 08, 2010 11:44 am
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The formulas got all jacked up in the post, I'll build them in a pic format in awhile and post them but for now it's...

Size of target in yards X 1000 / Size in mils = Range in yards
Size of target in inches X 27.778 / Size in mils - Range in yards

#23: Re: Minute of Angle - All you need to know. Author: Pizzaguy, Location: Oklahoma

Posted: Fri Oct 08, 2010 11:54 am
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Another little “off to the side” way to know what power you scope must be on to be “true” and what measure it is on max magnification is to take a black marker and draw 1” lines on it and place it @ 100yrds. (Also mark 3.5”) and then play with the magnification settings until on mil is 3.5” and also learn what one mil is at max magnification. Then do the math if 1 mil is 5” at 24X @ 100yrds then at 200yrds it’s 10”, at 300yrds it’s 15”and so on.

#24: Re: Minute of Angle - All you need to know. Author: Dawgdad, Location: On the Prairie

Posted: Fri Oct 08, 2010 2:33 pm
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I thought a minuet was a kind of classical music?

#25: Re: Minute of Angle - All you need to know. Author: Pizzaguy, Location: Oklahoma

Posted: Fri Oct 08, 2010 2:48 pm
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Dawgdad wrote:

I thought a minuet was a kind of classical music?

But it's part of the "don't ask, don't tell" thing, how do you know about it?

#26: Re: Minute of Angle - All you need to know. Author: Dawgdad, Location: On the Prairie

Posted: Sat Oct 09, 2010 5:27 pm
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Your secret is safe with me...spell checker only knows what are words not context.... Smile

#27: Re: Minute of Angle - All you need to know. Author: toddco,

Posted: Sat Oct 16, 2010 8:45 am
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All cool info. Would you happen to know anything about cosine angles? Also, another very good and user friendly app for the iphone and shooting enthusiast is the app called: Bullet Flight. In this app you enter your rifle/pistol information, load information, zero sight in, distance to target, wind, hit enter and it tells you how many moa to adjust for your shot. It seems very accurate if you put the correct information in to it. I have also read somewhere that 1\4" click moa scopes are not quite 1\4", is this correct?

Thanks,

Toddco

#28: Re: Minute of Angle - All you need to know. Author: Elvis, Location: south island New Zealand

Posted: Sat Oct 16, 2010 3:20 pm
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todco REREAD the last 2 lines of the first paragraph and the 3rd. my personal experience tells me to try out when sighting in as all scopes are slightly different. some adjust bang on and others are nothing like what they say. some dont move much then jump waaay over. I always adjust the amount I think is right then tap firmly on the turrents of the scope fire anothr group and have a look where the holes are. I also move my scopes 12 click one way then back 2 the other not just 10 the way I want as a engineer buddy who taught me heaps about shooting said to. It works for me so I do it.

#29: Re: Minute of Angle - All you need to know. Author: Pumpkinslinger, Location: NC foothills

Posted: Sat Oct 16, 2010 6:42 pm
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After making any scope adjustments I bump the butt of the rifle against something hard, like the bench top, to help it settle in. Then, as Elvis says, shoot another group.

#30: Re: Minute of Angle - All you need to know. Author: slimjim, Location: Fort Worth TX

Posted: Sun Oct 17, 2010 5:32 am
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At the range yesterday with a friend. He put in 5 clicks of windage in stages with a Leupold scope for 100 yards and groupings didn't move. Finally left well enough along. It was only 1/2 inch to the right. Fired many groupings. Seems one important aspect of scope quality can be measured by how precise the adjustments works. I haven't seen to many that adjust as they claim.

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