Hi,
I'm new to scoped rifles and I recently purchased a new Ruger American Rifle with a used scope mounted for $700 out the door.

I've been shooting with iron sights with no problems ever. With the scope I could not adjust the windage enough to bring the scope to my grouping.

I took it to the dealer and he took it out shooting and said that when the barrel gets hot, it's off the paper at 100 yards.

I'm somewhat disappointed that I shelled out that much cash for a $400 rifle with a used scope. Does anyone have any advice? Is there any hope to "save" this rifle? How can I find out if it's the scope that's messed up or if the barrel is jacked?

I appreciate any words of wisdom.
Thanks