I'm no pro, but I can tell you it will be as consistent as you are, which already sounds pretty darn good. 4/6 under a nickel at 40 is good shooting. Lots of trigger time and finding the perfect pellet will bring out the best in the gun, as with any other rifle. Sounds like you've gotten a winner!
Yeah I dont have much time with this combo but do have lots of time behind other air rifles. Ive had ny rws 36 for 19 years now. That seems like a petite toy compared to the heft of the 54. I see you're from Mpls. I grew up in the Maplewood wbl area.