RE: .177 cal Pellets???
with air rifles the velocity will vary between different pellets, your particular gun is advertised at 1100 fps that means the gun was tested with a lead pellet that was probably around 7 to 7.5 grains most of your hunting pellets will weigh 8 to 8.5 grains which will decrease your velocity quite a bit probably down to around 950 fps. from what I noticed heavier hunting pellets have better performance for shorter ranges like 15 yards or less at further ranges like 20 yards or further the heavier pellets dont seem to be as accurate mainly because they are lacking the velocity and just dont stay stabilized aswell as lighter pellets.
if you want the most from your air rifle I highly recommend using Gamo raptor ballistic alloy pellets these pellets are alot lighter than lead pellets at 5.1 grains, but they hit higher velocity and stay stabilized for a long way. I use a benjamin sheridan which is advertised at 800 fps but with the raptors my gun should be moving pellets closer to 1000 fps and in your gun they should push 1300 fps that would give you some serious long range accuracy.
just to give you an idea of just howmuch more accurate these pellets are at long ranges from my benjamin, I have the gun zeroed in for 40 yards I can consistantly knock empty shotshell hulls off my fence posts at 40 to 50 yards. And a few weeks ago I blasted a pack rat at about 50 yards. these pellets are freakin awesome.