G'Day Fella's,

450/David, it has been my experience that most rifles especially "Rat Gun Calibers" (that's Sub-.30 Cal for the uninitiated), need around 100 shots through them before they settle down and start to shoot, to their full potential.
Now by this I don't mean get a New rifle and shoot 100 shots through it and expect it to shoot!
I mean, first clean the barrel, then as described, Run the Barrel In and clean the barrel regularly in this first 100 shots.

Good luck with it and I hope it reaches your expected accuracy.

HooRoo
From
Hammer