That's very good accuracy for bulk Crosman pellets. Springers take an artillery hold and concentration to shoot well. My 2nd springer is/was a .177 Gamo. Forget the model. Looks just like yours without the whisper. 1000 fps with lead pellets, Actualy around 975 with Crosman pellets. It will group into 1-1 1/2'' at 25 yards with what it likes and into 2 1/2'' at 50 yards on a calm day with same pellets. The older Gamo guns like mine from around 2005 or so are violent recoil guns. when that trigger is tripped there's a TON of vibration. Now all the airguns I shoot are 22 cal so the Gamo sits in the closet waiting to find a kid that wants his 1st pellet gun.
