So many people have sent me emails over the years asking for Browndog’s and 4ked Horns turret wrap programs. These were developed for 308s and one is in MS Word and one is in Excel. Both are developed for a particular load and worse yet for a particular scope so they are useless except as an example of how to do it on a computer.
Back in 1979, before there were home computers and fancy stuff, I built a turret wrap that was accurate out to 1300 yards. So I have some knowledge of how to do it without a computer.
For the people who want a turret wrap but are not computer geeks, here is how to do it. If I got something backward then just say so and we will get it right for the next guys.
OK, Here we go!
1. Shoot your groups out to what ever range you are comfortable to and record the drops and temperature.
2. Grab your hex wrench and take off the scope turret
3. Take a scissors and cut a piece of plain paper about four inches long and 1/8 to ¼ inch wide. This you will make into a ruler for your dial.
4. Take the strip of paper and lay it up against and around your scope dial with one end starting at “zero” and with a very sharp pencil or extra fine point pen scribe the piece of paper for every mark on the scope dial until your get back to “zero” and cut it off there with the scissors . And mark the “zero”. Now then, this strip of paper will be your “ruler” for measuring out your drops on the next strip of paper you will be cutting out.
5. Take the plain sheet of paper and cut out a strip of WATERPROOF paper that is equal to the length of the ruler – in other words it will just exactly wrap around the turret. The width of the strip will be such that it will fit on your turret.
6. This part is a little tricky and you will have to do it on your own being as I am not familiar with the your rifle’s ballistics. Look at your scope dial and see how many MOA it has on “one revolution”. Look at the maximum range you want for your wrap to work for and see how many revolutions you will need. Probably at least two and perhaps three or four. Ok, so if your need two revolutions, then you will need to draw a line from one end to the other end of the last piece of paper lengthwise. If you need three revolutions you will need to draw two lines that divide the piece of paper into thirds –going lengthwise. Obviously, if you need four then you draw three lines and divide the piece of paper into fourths. The bottom part will be for the first part of your ranges that fit on one revolution. For example a Luepold scope will have about 12 MOA (or 15 –Mine are locked away at the moment) on one revolution of the dial and you will be able to get about 400 or 500 yards marked off on the bottom.
7. So now you have two little pieces of paper and are beginning to wonder if both you and I are crazy. Obviously yes, grown men cutting out paper dolls are crazy. Nevertheless until we begin to talk to ourselves we are OK.
Assuming you have a 100 yard zero then do the following: Consult your drop chart and find your drop from 100 yards to 200 yards. Remember to divide by 2 to get the scope MOA.
Take the “ruler” piece of paper and measure out the correct number of MOA from 100 yards to 200 yards on the second piece of paper on the bottom part of the paper starting from the right edge (yes it is backwards). This will usually be between 1.0 to 2.0 for a slow gun and a fast gun. Make a mark with a waterproof ink pen and writing very small write “200 next to the mark. Now consult your drop chart again and find the drop from 200 to 300 and divide by 3 and measure with your “ruler” paper that amount from your 200 drop and mark and write 300. A rifle will drop an additional 2 or 3 MOA from 200 yards to 300 yards. Repeat this until you come to the end of the first line.
8. Hitting the end of the Paper. Things will not work out evenly so you will reach the end of the paper somewhere in between 400 and 500 yards or between 500 and 600 yards depending upon your scope and your cartridge. Just remember that the paper will wrap into one seamless piece of paper and when you come to the end of the bottom section just move on up to the next section. Remember you drew the lines dividing the paper into thirds or fourths? Yes you did that in #5 above and now we know why!
It is OK. Using your ruler just measurer from the last yardage one the bottom row to the end of the paper and then begin back on the other end on the next row such that you get all of the MOA accounted for.
Continue on the second row up measuring and marking EXCEPT scribe your mark in a different color ink and make it come all of the way down to the bottom of the paper so it will “index” with the mark on the scope. If you don’t understand what I am saying DO NOT TAPE ON THE WRAP UNTIL YOU DO. Continue on, expecting that if you are slightly confused you may have to re-do some of your work.
9. Measure and mark until you have all your yardages done.
10. Take your marked up piece of paper and wrap it around the turret lining up the beginning with “zero”. Does everything line up properly and if you spin the dial would it make sense to you. Can you tell where the 600 yard mark is and how to dial to it? 600 yards will be on the second row so you need to be able to get it lined up. The same thing for the third row. At 800 to 1000 yards you cannot be one click off. Everything must index correctly.
11. So you finally have a turret wrap that is correct. Take a piece of clear tape and tape the beginning end to the turret lined up with “zero”. Wrap the paper on around and tape the end to the beginning. No then I doubt that you used water proof paper so you will need to tape over the whole wrap to waterproof it.
12. Shoot your rifle and verify everything is correct.
13. Depending on what ranges and the sizes of your animals you hunt you may need a correction factor for temperature. A 50 degree Fahrenheit temperature change will cause a ballistic change of about 0.5 MOA at 1000 yards. Said differently you will miss by 5 inches at 1000 yards if you use a drop chart that was developed in 70 degree weather and try to shoot in freezing cold 20 degree weather.
The velocity change due to cold powder is something different and I cannot help you if you shoot cold powder. You have to keep your cartridge warm. If you have been hunting for hours in the snow with a cartridge in your chamber and need to shoot 1000 yards get a warm bullet out of your pocket. The anti-BDC people will claim that you missed because of the BDC when it will really be cold powder.
There is a change due to altitude that you can determine by running your particular bullet and velocity on JBM Eskimo or other good ballistics program by only varying altitude. Don’t worry about barometric pressure at this point in your efforts. Altitude will be good enough for a turret wrap.
Finally remember that the bullet drops more at the end of a 100 yards stretch than at the beginning so if your elk is at 775 yards you would dial up to 700 yards and then go 75% of the way to 800 yards and then give it one or more extra clicks. If it had been a 725 yards you would have gone to 700 and then 25 % of the way to 800 yards and backed off a click or so. Is this clear? I hope so, because it becomes important way on out there.
Remember that this wrap is for a particular bullet with a particular BC and velocity. If you decide to change then it is back to the scissors and cutting out paper dolls to make a new wrap.