assuming you have no strong preference yourself, go with what the above people are saying: G17 for factory ammo, G22 for custom loaded ammo. Some people have a strong preference for 9mm over .40/.45/etc (like myself), so even if I was shooting in a division where Min/Maj makes a diff, I'd still shoot 9mm. Some people love .40, like a friend of mine who shoot a stock .40 cz-75 in Production, with factory ammo (NOT downloaded), and he loves it - doesn't want 9mm... So, generally, it depends on your particular situation and preferences.