I get my best accuracy out of 40 gr V-Max with 13.5 gr Lil'Gun in Rem brass with CCI 400. The OAL is long, about 1.9", but the Handi chamber will handle that without a problem. It isn't a benchrest gun, but it will still shoot less than 1" at 100 yards. The 35 gr V-Max hasn't shown me much that's good and neither has the 45 gr Nosler solid base.
Winchester brass may be a little thicker and it holds about 0.5 gr less powder Win and Rem bulk 45 & 46 gr bullets don't shoot too good, but make pretty good plinking rounds.
My 9 year old and 11 year old grandsons don't have any problem with the recoil (which is very light), but make sure to use ear protection!
BTW, I'm using the 20" barrel that comes with open sights that's listed in the Barrel Accessory Program.