Light strike issues with a VURSAN model 2000

[CHAM12]

I have a VURSAN M2000 same as the stoger 2000 but with not all the same parts it is having light strike issues it will do it on first or second round rack a new one and it goes bang few more go bang then does it again. I have tried a few rounds federal remington and some other stuff does it with all. Gun is clean i guess stoger bought out vursan and changed a few things mainly the trigger spring i ordered one from MANN & SON they make all the parts for stoger and the trigger spring is like that of a M870 whick is a stick spring not a ring spring That looks like a big loop. Any help with this issue would be great the gun is for my girlfriend to hunt quail. Cant get a bird if gun dont go bang. Thanks