So I have an Elk hunt the second week of September, and like a total moron I choose to change the scope on the only rifle that I had...... I had just gotten a new rifle and figured that it wouldn't be an issue.

Here is my set-up and my question:
Browning X-bolt White Gold rifle in 7mm Rem mag.
Topped with a Swaro Z3 Ballistic turret scope, and the browning x bolt rings.

I may be jumping the gun with my concerns, but went shooting it for the first time last week and could not get better than a 8-10" group at 100yds (off a bench) I was using the Hornady Superformance SST in 154 & 162 Grains. I figured that something must be loose, but upon investigating I found nothing to be loose. I remounted the scope and now I have 5 new factory loads to try my next time out. Is it possible that the gun just doesn't like that round? My 5 new loads I have varied weight, and Velocity as much as I could find to see if there is a "sweet spot" with this rifle.

Is there anything else that I should be trying? I was shooting the other guns I took just fine, and never let the gun get hot...