If it's anything like other nelson pumps out there (which it almost certainly is, although since I don't have one yet I can't be 100% sure), you can get a maddman lp cocker spring kit - the main springs are same in both '99+ cockers/snipers and nelson based guns (i.e. hammer, phantom, etc). Only problem is that you'll need to cut a couple coils off the valve spring to get them to work in a nelson based gun.
Your only real alternative is a CCI phantom spring kit. You get three main spring choices, same as the Maddman kit, but only one valve spring choice (although unlike the maddman kit this will fit other nelson based guns without any modification necessary).
Other than spring kits, try polishing up your internals. I also find a little oil works wonders on the hammer/powertube/antikink/tpc/bolt, although just a drop or two (I use a pps oil bottle that uses a little nail polish brush as opposed to just a dropper).
As said, you might even be able to use other nelson guns parts (anti-kink/tpc), although I could be totally wrong about this given I don't have a hammer 7 and haven't seen any indepth reviews.
Good luck! From what I hear they're not so bad re pump stroke.