First off you need to find out if your scope is a true mil-dot scope or not. If it's not a first focal plane then it's not going to be a true mil-dot. That being the case, you need to find out what your subtensions are. As an example, my scope is a Millet 4-16x50mm mil-dot. But it's a second focal plane scope. So my mil-dots change depending on magnification. Over 10 power, my mil-dots go from .036 to .025 inches at the muzzle, which means they are 2.5in at 100 yards. This actually makes my calculations easier, as it's easier to multiply 2.5 You may have to actually shoot your rifle to figure out what your subtensions are.
Then take your average coyote. 3-4ft long (36-48in), 18-24in at shoulder.
(Target size in inches x 27.772)/#of mil-dots
OR
(target in inches/# of mil dots) x 27.772
Or you can use the formula:
(Target size in yards X 1000)/#of mil dots= Range in yards
I ranged a coyote that came in under my 1st mil dot. I figured the coyote was about 18 inches at the shoulder as it seemed to be an average looking coyote. Crunching the numbers I got 499.896/.75 mil dot= 666 yards. I made my adjustment and sent my first shot. I was a little high, probably too generous with my first adjustment using Kentucky elevation and the coyote looked up, so the bullet must have whizzed just over head. The second shot resulted in a downed coyote.
Now if you plug that formula into an excel spreadsheet, you can print out your DOPE chart. I laminate the chart and tape my chart to the inside of my rifle stock.