Not to be insulting, but I have to ask, how do you know it's the rifle? You didn't mention what rest you were shooting, and you didn't make any statement about how big your groups are, and you didn't mention anything else to make reference to how well YOU can shoot, making me 100% certain it's the rifle's fault.

If you're shooting off a controlled rest (sandbags or adjustable rest, or at least a bipod) from a solid base (not over the hood of a truck, or offhand), and are getting 4inch or bigger groups, then the next thing I would look at is that 1.75-4x scope. Off the top, I'm guessing that's a Bushnell Trophy, 1.75-4x32mm scope. FOV at 100yrds is 75ft at 1.75x, and 29ft at 4x. The PROBLEM with that is that a 1" group, out of a 29ft FOV, you're talking about 0.3% of the FOV, or 0.15% margin for error. Basically, if you move 1% from one shot to the next, you're talking about 3.5" groups. Comparatively, the 3" groups at 50yrds that you mentioned would STILL only be 1.7% of your FOV... Holding within 2% is doing pretty dang good.

Moral of the story, is that 1" groupsat 100yrds is asking a LOT out of a 1.75-4x scope.

On a relative scale: 1,000yrd shooters often use 30x powered scopes, such as the 8-32x56mm Nightforce BR scopes. These have FOV's of 30ft at 1,000yrds. Basically, shooting a 1" group at 100yrds with your 1.75-4x scope has the same margin for error as shooting a 1" group with a 8-32x56mm Nightforce scope AT 1,000yrds!!!!

Or consider a 3-9x40mm scope. A 1" group at 100yrds with that 1.75-4x scope is the same as shooting a 1" group at 250yrds with a 3-9x40mm scope. 1" at 250yrds is amazing, 1" at 1,000yrds (above 8-32x56mm scope) would be world record level shooting, so you really have to realize what you're asking from that little 1.75-4x scope...