[kraigwy]

Having coached the AK NG Rifle team for years, I've noticed that most vertical stringings can be cause by at least three differant reasons:

Breathing: Breathing while shooting the string instead of stopping the breath as the trigger is pulled.

Improper or loose sling: Sling not high enough on the arm, loose and slipping etc.

Poor position: Loose position, elbow and/or knees slipping during the string.

Another, rare posibility is loose rear sight, thats a simple check, put your thumb on the rear sight and see if you can push it down. This is not likely the case as you would notice the differant impact between strings.

The Cure is to have a coach w/spotting scope watch you shoot. Seeing which bullet is where. Is the first round on, and the string walks up, etc.

Go to the CMP website, (bookstore) and get a copy of the USAMU Service Rifle Guide. Best $6.95 you can spend for rifle shooting.