I also have a 410K .22. the aa fields are 16 gr which IMO is plenty.If you want more weight then then you would have to compensate for a lower velocity and a more pronounced trajectory.I've found that the aa fields work nice for me.But if your doubting the pellet then you dont have full confidence in your combo.I may get some different views to this but Eley Wasps 5.5 mm are damn accurate in mine and also put out a little more ft/lbs, 11.87 last time i put a string through my skan chrono.So maybe you could give them a go and see if it works for you.I've had the odd rabbit go on a mad un after i've placed a pellet in its brain but you've just got to remember that there are just so many variables with each individual shot no two will ever be identical