175m/sec with 0.45gram pellet.
Gamo Hunter Extreme 1650 FPS - Air rifle .177 Cal Air Force TalonP 900 FPS air pistol .25 Cal Hatsan AT P1 Air Pistol .177 870 FPS The Air Force TalonP is faster in .25 Cal than the Hatsan .177 Cal
The Eclipse came in 3 different calibers. .177@925 FPS - .22@710 FPS - .25@620 FPS. It was mfg between 1990 & 1996
That would most likely be the Hatsan AT P2 PCP Air Pistol at 870 FPS
Rodents
If you are reffering to speed, there is no calliber that can beet the .177. You can get a .177 gun that shoots anywhere from 150 FPS to 1200 FPS. There is a catch though, because energy is calculated by mass X exelleration, you can learn that where the .177 has high speed, it has very low mass. If you got a .20, .22, or .25 calliber gun, than you would have very low speed but very high mass.
For an air/piston powered .177 BB gun - anything less than 200 feet per second (fps) For a CO2 powered BB gun - anything less than 300 fps. For an "AIR SOFT" gun - anything less than 150 fps.
Currently it's the Beeman RX-2 at 1125 FPS in a .177 pellet
It all depends on the power plant inside the gun or rifle. They can be as slow as 150 FPS (Feet Per second) up to 1,500 FPS when fired from a high powered air rifle.
With the right pellet you you can, But it should be a hunting Pellet (Hollow-point) and it should be a heavy pellet not a light weight pellet with at least 900 to1000 FPS.
I doubt it.
A pellet weighing 7.9 grams can not exceed 826/FPS See the link below
The 620 is a 4.5mm or .177 caliber pellet rifle and is rated around 450 FPS.