I recently got a Beeman R1 rifle used in .177 to control arboreal rats.

I'm surprised by how inaccurate it has been for me so far, about 6 inch 25 yard "groups" off the bench in calm conditions. I tried a couple different hunting pellets.

Are there any accurizing steps I might try with it? I'm not real keen on gut-shooting Fox squirrels around here (if I hit them at all!)!