DadsArmyDean

Hello Hoping someone can help me with a gas shotgun issue I have a Golden Eagle M8879 gas shotgun and for some reason it will only cock when the 30 round shell is about half full, if I fill it up to the full 30 rounds it will not cock at all its just locked solid until i remove the shell, also the same with the drum mag if the drum is loosely wound then it cocks but fully wound again its locked solid. Any help would be greatly appreciated as I love this thing. Thank you