Thread: Vertical stringing

Hi all, I have been developing a load for my son's Rem 260 and it is very consistent sideways, about 20mm from side to side of the group (5 shots), however it seems to disperse on the vertical axis over 65mm at 100m. I am shooting from sandbags front and rear and feel comfortable with the technique. The action is a Brno 601 with a Trueflight barrel mounted. I am using Nosler Ballistic tips, 140 gns and feel it should shoot better. It is also action and pillar bedded with no barrel contact in the channel. I was wondering if there are any rules about seating depth which may help shrink the vertical dispersion? Any thoughts greatly appreciated.

Regards Ruger7mm