Should I have been surprised?

Shooting my RED WOLF 22 standard gun. Shooting at 50 yards at a splatter target tacked to a 2 ft square card board box. The 18 gr JSB even in the wind (which was light) hitting no worse then 3/4 inch. I had some 25 gr JSB and they shot so bad I probably couldn’t have hit the box every time.
Ive read some about pellets spiraling. Think that could be happening? I just could not believe 7 grain difference would make that dramatic of a difference. I shot some a day or so ago and same thing. On that day I was shooting on a plain paper target and it appeared to me that some of the pellets had key holed as well . ( more info) 
 
I shot groups yesterday with the JSB Redesigned .22 cal., 25.4 gr. pellets at 75 and 100 yards from my Impact X with the 600mm slug barrel at ~ 930 FPS, and the groups were mediocre. 

My conclusion is that I will not use these pellets at distances beyond 45 yards.

I intend to try the FX Hybrids at the distances beyond 50 yards in this Impact .22 cal.