That is normal as that is where the air enters on the pump stroke, one should make sure to let it breath it in on every stroke, to get the most air stuffed in the valve for each stroke. 880s are known to be one of the easiest to pump, next hurdle is mastering the heavy trigger pull.
Thanks for that reply. I didn’t have much time to shoot it today. I have a 760 I shoot some and don’t hear that air noise so wasnt Sure what to think. Do hear the same noise on an old 66 though. Yes the trigger was pretty bad and accuracy also but I just shot at 25 yd spinners without much success which was disappointing. I’ll try some paper tomorrow, closer.
Thanks Wepster. I was looking at the front site and wondering if what looks like a plastic pin sticking up proud slightly in the sight had to come out first. Now I know. I'll search that. I suppose you took the barrel off also?