You probably know this but, make sure you have a consistant grip on the forend and the rear of the stock the same in the bag. Make sure the sling swivels aren't rubbing on the bags. Light barreled guns show vertical really easy if your form changes slightly.
You could also try it with a business card between the barrel and the pressure points just to see if that changes anything. Definately check the Talley screw as mentioned above. I've had them too long too. 50g of big game should have pressure up there but I've had lots of vertical with some light loads of ramshot powders and huge velocity spreads. When I run ramshot a a little higher pressure things usually come together. My faux ti didn't like the Big game 120 NAB combo so I went back to RL-15.
Bb
