Depinger - REQUIRED!
I'd disagree about pellets, best stock power round is the Benjamin Nosler at over $1 per shot. Best cast round would be (for mine) Lee 356-125-2R mold at around 125-135 grains depending on alloy. These are the two that I had 3 inch groups, on a bipod, with iron sights at 50 yards. For me that's a decent group, take shooter skill into the previous group size and remember that at 50 yards that 3 inch sticker is the size of the front post, at least to my eyes.
Now then, since that time, I've upgraded the power so everything is out the window, and I need to put a scope on it to get better results. Mine is now also regulated with the Pitbull kit, no more depinger needed because the regulator seems to take care of the issue, at least 10 shots regulated.