Am a lazy shooter....a hard-eyed visual exam of high quality pellets is all they get. Crosman's have been among the worst in that regard, being VERY variable between tins/boxes on the number of visual rejects.
Diameter plays a good part in this,,,with once in a while a good LOOKING pellet chambers exceptionally hard (indicating it's "fat") or exceptionally easy (indicating it's "skinny)...the mal formed ones I pick out (and often just "bugger flick" out into the weeds rather than save some for some non-critical use)
So some of my shot strings posted are actually better than they would be...when I catch a questionable pellet, either it's put aside for trigger adjustment use or it is "flicked" over the fence. If it passed visual inspection and I noticed a big difference in chambering, it gets shot in the dirt rather than at the target.
Pretty much every way you can think of to miss-center the center of the chronograph will give lower speeds (the pellet having to actually travel farther between light sensors)../..I really don't believe that the little "chip" that runs the chronograph has a reason/ability to lie...so even with visual inspection and tactile rejection, there are occasional "off" shots.
Could be a lot of things,,,from some internal void, a dimensional difference I couldn't feel on chambering, or some undetected damage in chambering.
And I really don't care (or am able to investigate the pelletafter is mushes itself out in the back stop)...will just try other pellets (I'm not that enamored with the cheaper Crosmans to spend the time sorting them when they don't immeidetly shoot well).
Any way,,,,by best Gaultlet strings run at about 25 shots for 25 foot pounds inside of 4%,,,and act "right"with pellets other than the 14.3gr. Crosmans (16gr. AA's,18.1gr. JSB's, or 21.1 Ggr. H&N's)