I bought a G80 second hand about a year ago in .177 cal and thought at the time that is was quite powerful and I recall chrono-ing it and it produced about 10 ft-lb if I remember correctly.

It was a rather strange variant of the G80 in the respect that someone had replaced the foresight with a ring on a post screwed into the muzzle which together with the open square notch rear sight giving quite an odd sight combination (I guess the original front sight was a blade), but I only paid £35 for it so I am not complaining!

Aubrey