Is this 1077 powerful enough to take down small game at short range..like a squirrel?
It is not powerful enough to be recommended for that usage.
how many shots until i have to change the co2
There is a lot of variables in this. For the most part you will see a decrease in velocity after about 4 clips. This does not take into account many variables including temp that will greatly change this approximation.
This units "Piercing Tube Cap" does NOT employ an O-Ring or Seal?
The CO2 seals on the front where it meets the piercing pin so it in not needed where the cap is threaded.
whats the fps
625 fps according to the specs tab
What laser and flashlight do I use with the crosman 1077?
This will work with the scoped combo: http://www.pyramydair.com/s/a/BSA_Varmint_Hunter_Precision_Laser_Sight_Light/1046