Like the others said, probably a combination of likely factors...
But, let's start with one that hasn't been discussed...
It's a used rifle...
And an older one at that. The AccuTrigger has been around for ten years. What's the condition of the bore, and crown?
What type of cleaning did you do on it after purchase?
I have a pre-AccuTrigger Savage with the adjustable 3-screw...you can tweak them to be pretty decent, but if you haven't- it might have a pretty hard pull.
You also (obviously) don't have the AccuStock- so what stock is the action in- is it bedded, or at least, have pillars installed?
It could be as simple as the barrel and stock on an older rifle..
Not to mention shooter error, ammo, etc. as mentioned on top of that.