Vulcan # 2 in 177

Got my 177 vulcan in , Cocking arm on left hand side sucks for me any way, Went to change it and one of the tiny torx screws was already striped , 177 Pellet 10 gr JSB pellets had a few jam on me , Stuck past the cocking probe.
Can not see any reason why the gun is jamming, Unless I am cocking the cocking arm to far back and the pellet is just falling back in the breech behind the pellet probe . Also there is major puff of air hitting me in my eyes when i fire the gun,
I cleaned the barrel tonight , So I am not saying anything about accuracy in till I get to shoot it with a clean barrel, Lots of black junk
Its as loud as my 22 Mutant un muffled , a very sharp crack, Yep Donny will get some money from me.
Mike