Zeroing Rifle for Longrange shooting

[Desert Fox]

I've always zeroed my rifle at 100 yards, but after reading Kirby's post on another thread that he does his at 500, I wondered, How does the rest of the guys here set their zeroes! After all I have two groups that I've shoot a couple of days ago with both my 308 and 338 that validates Kirby's method. I was aiming at the center square.

Here's the 338 Lapua's 3 shot group - 1" low about 2" left could be the wind!

Here's the 308 Winchester 3 shot group - 1.5"high about 1/2" right could be spindrift and scope click error!

Need help in analyzing the group. The condition were about the same although it was a week apart.

 

[davewilson]

i like to zero at 300. if anything happens quick, you're good to about 350. my recommendation would be to shoot a group at 100, crank the scope up 10 moa, shoot a group, then repeat with 20 up on the scope. this will eliminate the spin drift and tell you if your scope is tracking vertically or not.