Not sure if this belongs under optics or ammo, but here i go anyway. My new rifle has recently arrived and i am looking forward to bringing it to the range. I have a Remington 700P, 26" barrel, 308 win, custom bedded with reworked trigger, bipod, 20 MOA warne rail, and a Leupold 6.5 - 20X MK 4 mil dot scope. I am trying to do up a range card of sorts so i know how many "clicks" to adjust my elevation for at different ranges, but am finding it confusing. I am using Federal Gold Medal Match 168 gr HPBT rounds, and got some ballistic data off their interactive catalogue. According to their program, i have to zero my rifle at a certain range, what range should i be "zeroing" my rifle to in order to make up this range card? How do you guys do up your range / elevation adjustment cards?
long range confusion
- Thread starter johnny rotten
- Start date
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- Hillbilly shack in the boonies
It really don't matter, 100 or 500 , some folks say its better to zero for 500, right, 
, I zero @ 100 , copy data, move to 2,3,4,5,6,7,8 hundred , and copy data for each . Now this gives you what that cartridge is doing, change and part of that and it all changes.
Windage is just that, if you know the speed, and can dope for it, mark both numbers down, after a while this part gets easier.
Oh sorry , for how to, I go... rotations , minute, part minute (example) 4 - 3 - .75
Minute you read off the dial, part is broken into .25, .50, .75 which is 1/4, 1/2, 3/4, ...
Now I have not looked at my log in a long time, so someone else can correct me here.
, I zero @ 100 , copy data, move to 2,3,4,5,6,7,8 hundred , and copy data for each . Now this gives you what that cartridge is doing, change and part of that and it all changes. Windage is just that, if you know the speed, and can dope for it, mark both numbers down, after a while this part gets easier.
Oh sorry , for how to, I go... rotations , minute, part minute (example) 4 - 3 - .75
Minute you read off the dial, part is broken into .25, .50, .75 which is 1/4, 1/2, 3/4, ...
Now I have not looked at my log in a long time, so someone else can correct me here.
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I've found that published ballistics can be way off on factory ammo. If you don't have the range to actually measure the bullet drop from line-of-site at every 100 yds, then best to use a cronograph and a good ballistics program such as ExBal.
I personally zero at 100 yds, measure drops at distance for correction, get the avg muzzle velocity and range conditions, then use QuickLoad/QuickTarget to create a long thin drop chart for every 25 yard out to a 1000 for a specific altitude, temp, barametric pressure (my hunting grounds) and keep it on the rifle.
One nice trick is to install a "clickstop" modification to your vertical turret knob (drill a tiny hole in the top of the knob, tap it, and put a small allen screw in and adjust it so you're knob stops turning down at your zero point.
JK
I personally zero at 100 yds, measure drops at distance for correction, get the avg muzzle velocity and range conditions, then use QuickLoad/QuickTarget to create a long thin drop chart for every 25 yard out to a 1000 for a specific altitude, temp, barametric pressure (my hunting grounds) and keep it on the rifle.
One nice trick is to install a "clickstop" modification to your vertical turret knob (drill a tiny hole in the top of the knob, tap it, and put a small allen screw in and adjust it so you're knob stops turning down at your zero point.
JK
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Jay Kyle said:
Yep. There are so many variables (ambient temperature, barrel length, chamber tolerances, # of grooves, etc.) that will influence the velocity of your particular gun/ammo combo that you will need to chrony that load, find a mean average velocity and run your numbers through a ballistics program.
At long range, the elevation setting can even vary during the day because of changes in the temperature, etc. For best results, zeros need to be confirmed by actual range testing with a particular rifle and particular batch of cartridges. and even then fluctuations will be observed. Factory range calibrations engraved on the sight are an approximation; there are far too many variables for the markings to be anything else.
What others have said about variability is correct.
I establish and record the elevation zero for my rifle and ammo at as many of the distances I will be shooting as opportunities permit and then use ballistics data from a ballistics program, to fill in the gaps between the distances I have tested. I re-run the ballistics program to tweek the inputs until the ouputs match my confirmed zeroes at the different measured distances that I have actually shot.
I establish and record the elevation zero for my rifle and ammo at as many of the distances I will be shooting as opportunities permit and then use ballistics data from a ballistics program, to fill in the gaps between the distances I have tested. I re-run the ballistics program to tweek the inputs until the ouputs match my confirmed zeroes at the different measured distances that I have actually shot.
NavyShooter
CGN Ultra frequent flyer
- Location
- XMU Local .303
As is mentioned above, consistancy is the key.
If you change one portion of your system, your numbers will change.
IE, with your rifle, scope, base, stock, rings and bipod as is, and the same ammo, you should find consistant results.
Change your scope, your settings will change.
Change your ammunition, your settings will change.
Change ###X (insert item here) and your settings will change.
If you keep the mechanical system of the rifle, scope, ammo, etc consistant, then it comes down to correcting for the conditions and range that you face.
If you're constantly fiddling with new ammo, putting a new scope on, etc, things will always change, and you'll never get the hang of it.
NavyShooter
If you change one portion of your system, your numbers will change.
IE, with your rifle, scope, base, stock, rings and bipod as is, and the same ammo, you should find consistant results.
Change your scope, your settings will change.
Change your ammunition, your settings will change.
Change ###X (insert item here) and your settings will change.
If you keep the mechanical system of the rifle, scope, ammo, etc consistant, then it comes down to correcting for the conditions and range that you face.
If you're constantly fiddling with new ammo, putting a new scope on, etc, things will always change, and you'll never get the hang of it.
NavyShooter
Thanks for the great info guys. I did some more looking around, and should now have enough information to do up a scope adjustment card. Hopefully a more experienced shooter at the range may have some helpful hints too.
