Getting the most out of the Diana stormrider

 

So I ordered a .22 stormrider refurb from pyramyd for my 14 yr old sons first pcp repeater 

he is shooting the Maximus hunter right now and doing well with it but after shooting my urban a few times he has decided he wants a repeater 

he shouldered a .177 stormrider and loved it so we decided for $150 shipped we would give the .22 a go 

while the gun looks great and is light weight. It seems to be hit or miss on performance some guys say mine shoots great others say mines a shotgun 

I have already ordered a rocker 1 ldc and extra barell band for it but I'm wondering if there's anything else I need to do to get the most performance out of it ?? 

i will do the normal barell cleaning and tightening of the screws as I do with All new ag s Anything else I'm missing ?? 

Should I try to find a bigger transfer port for it ?? Any o rings I should replace in it before I start shoooting it ?? 

Thanks for any info hopefully we can build him up an accurate little 35-40 yd hunting rig 

pcpfan37