OK update , BH you were spot on , thanks , +! for BH yay
OK so also spoke just now to Plinkton the USA STYER Dealer , so as you said the mags in both the new pro and x with round magazine , and the one you showed in video ,
SO the barrels in these Styers are held in with 3 screws 2 near magazine block and one in middle of barrel under scope , SO the screw closest to magazine , it is designed and drilled on an angle so when you tighten it , the barrel moves to the magazine , and the next screw pulls it away from the mag izine and the third screw just locks down , so , the correct way is to install the magazine push in barrel and tighten front screw so mag can just turn freely then tighten the others , and then index and shoot , no air should leak and mag should spin freely
LOU