i have taken a squirrel with a bsa supersport xl using jsb exacts (.177) at 50 yards. neck shot, by the time i got to him, he was dead. i trust this gun and my 350 mag at 50 yards using jsb exacts. there are 3 things to remember in "one shot, one kill" shooting......shot placement, shot placement, shot placement. also, you must remember that 1000 fps is measured at the MUZZLE. that is not the fps at 30 yards out. that number reduces dramatically at longer distances. what equates to 15 fpe at the muzzle may be as low as 6 fpe at 30 yards depending on the gun and ammo being used.
this is only my take on hunting with a springer. i'm sure others with more airgun experience than me will have a better take on it.