There is absolutely no way I would use Gamo PBA pellets.
It isn't just their light weight, but low ballistic coeffecient that is a problem. They don't carry enough foot pounds of energy to the target at the distances I need to shoot.
My .177 R-9 will deliver over 9 ft pounds to the fifty yard line shooting Crosman Premier Lights and over 8 foot pounds with Beeman Field Target Specials. They'll penetrate far enough into a bunny to kill it clean, every time, all the way out to 50 yards and a tick beyond. With .177, even with a weenie little 14 ft/lb M.E. gun like mine, lack of penetration on game normally isn't a problem, even with 'normal' pellets.
Besides, I much prefer shooting .20 in the field and Gamo doesn't make 'em in that caliber! That's okay, 'cause as long as I can get FTS's in .20, I've got all the small game killing thump I need.
-JP