Pics might help.
Are you sure the new forend is letting the slide go all the way back?
The only time the elevator doesn't block the ejection port is when the slide is fully rearward and if the new forend doesn't quite fit it may be dragging on the back of the barrel where it's fatter and not letting it slide all the way back.
Are you sure the new forend is letting the slide go all the way back?
The only time the elevator doesn't block the ejection port is when the slide is fully rearward and if the new forend doesn't quite fit it may be dragging on the back of the barrel where it's fatter and not letting it slide all the way back.