Just put 6X24X50 Sightron SIII on my Remington Custom Shop 7mm Rem. Mag. It is very clear and adjustment is dead on. I guess I'll find out if it stays that way.
I would pull the bullets and start over. As mentioned earlier, it could be the powder or the bullets, but something is not right. Check bullet diameters as well as weight. also do you have any other powders sitting around ?