Developing my dope...?

[81gtcoupe]

I am new to long distance precision shooting. I have a rifle in .308 and a scope and have zeroed in a 100 yards. The long distance range where I shoot goes out to about 650 yards. I want to start shooting at longer distances.

I understand that going from 100 yards to 200 yards to 300 yards, etc. requires me to adjust the scope's elevation to compensate for the bullet's drop. I also understand that once I've figured out how many clicks of elevation I need from my 100 yard zero to reach each distance, I can make a write down those numbers and keep them for future reference (i.e. dope). The same goes for windage when the wind is blowing.

However, how does one actually go about figuring out how much elevation is needed at each distance? Do I simple put a target at 200 yards elevate the point of aim by 10 clicks and see if I am on the paper. If not, then raise it another 10 clicks and keep doing this until I get it right? Or, is there a way of knowing about how much elevation I will need at each distance given my rifle, scope and calibre? Can u give me more info?

 

[cwh]

JBM - Calculations - Trajectory

www.jbmballistics.com

You can start with estimates on velocity and build a chart with jbm or others. Then shoot to confirm. A chronograph will get you a better initial chart, bjt you are still going to want to shoot it to confirm.

Someone who isn't typing on a phone can expound or tell me I'm full of shit.

 

[Driftin']

What scope? Is the reticle/turret adjustments in mils (mil-radians) or moa (minute of angle)? JBM is the way to go to build a trajectory table to whatever distance/intervals you want. You can set output in mils or moa to match your scope's reticle when inputting required muzzle velocity (mv) and bullet ballistic coefficient (B/C) into the program. If you're using factory ammo, you can get that info directly from them and the bullet manufacturer's websites. Set lateral wind at 10mph at 90 degrees for wind drift, making it easy to ratio output for field applications (7/10 * 10 mph wind drift output for 7 mph winds, etc.)

For a 308, I'd zero at 200 yards rather than 100. Input those two zeros into JBM and look at what happens out yonder in the program's output to see what I'm preachin'. Having an optic with mils or moa on the windshield will preclude you from having to spin turrets when shooting on either side of your zero distance or sliding wind. Win-win.

 

[Dude270]

Good info in the above posts

 

[Big Stick]

Go Ballistic AE,fuck the chronograph and never look back.

This assuming glass that tracks,repeats and holds zero.......................