I just purchased a mil-dot scope and had a question related to its use. The best way to ask my question is by providing an example, so here it goes. Lets say that you have used you mil-dot equation to calculate that you are exactly 1000 yards from a stationary target. You have zeroed your rifle in at the range on the same dayfor 100 yards, the temperature hasn't changed, the atm pressure hasn't changed, and there is absolutely no wind what-so-ever to affect your shot. The next thing done either by you or your spotter is to look at a ballistics table, so lets say that for your 1,000 yard shot, the bullet drop is 20 inches. My question is, How do you figure out how many minutes of angle you need to adjust for on the dial in in order to be zeroed for this shot at 1,000 yards when you started off zeroed in for 100 yards. Is there a formula for that too, so that no matter what the distance is between you and your target, you can easily adjust your scope to be zeroed in at the distance?

-- Drew G (goldman5@acsu.buffalo.edu), February 17, 2003

Answers

Sierra has their exterior ballistic program "Infinity". If you feed into this program the bullet size, the bullets B.C. and the muzzle velocity you are shooting, it will give you a read-out in 50 or 100yd increments out to 2000yards. Each one of these increments will contain your bullets "drop in inches" data. Simply divid the following numbers into the drop in inches catagory and obtain the minute of angle data you require! @ 200 yds use 2.094, @300 yds use 3.141, 400= 4.188, 500= 5.235, 600=6.282, 700= 7.329, 800= 8.376, 900= 9.423 and 1000= 10.47. A illustrated example goes like this: a 308 168gr bthp w/ B.C. around .475 traveling at 2800fps at 1000yds= 338.2inches of drop divided by 10.47= 32.5 minutes of angle! This would be the adjustment required to impact right on at 1000yds having a 100yd sight in on your rifle/scope system.mkh

-- Mike Hinde (mike@jrharchitecture.com), February 23, 2004.

Look at a moa or Minute of angle like a slice of pie. The further you get from the center of the pie the wider the slice. So with 100 yards being 1 inch, 200 yards would be two times that, or 2 inches, and three hundread yards, three inches, out too a thousand yards would be ten inches. So if your gun is zeroed in at one hundred yards, and the ballistics table says you have 56 inched drop at 1,000 yards you would divide the 56 by ten. Ten is the number of inches in a thousand yards or ten inches at the wide end of the slice of pie, and you would get 5.6 inches drop for the thousand yards. If it said 56 inches drop for 800 yards you would divide 56 by 8 and get 7 inches. or 56' / 8=7'. Pretty easy, Steven Shaw

-- Steve shaw (Stevenshaw@cox.net), June 03, 2003.

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-- D LITTLE (DL_AUDIO@YAHOO.COM), February 23, 2003.

THERE IS NO FOOL PROOF FORMULA THAT CAN TELL YOU HOW MANY CLICKS TO ADJUST YOUR SCOPE. THERE ARE SIMPLY TO MANY VARIABLES. THE BEST WAY IS TO FIND YOUR ZERO AT SEVERAL DIFFERANT DISTANCES, 100, 150, 200, 250...ETC. MAKE SURE THAT YOUR ARE USING THE SAME AMMO. ACROSS THE BOARD. HOWEVER SOME SCOPES DUE COME WITH A DROP CAM FOR VERY SPECIFIC BULLET BALISTICS, THIS WILL HELP SLIGHTLY BUT STILL NOT DEAD ON. GOOD LUCK AND HAPPY SNIPING

-- D LITTLE (DL_AUDIO@YAHOO.COM), February 22, 2003.