Try rotating the mag. If it's stiff it could get pushed out by the indexing post. You can open it and compress the spring between thumb and forefinger. Just a tiny bit at a time til its rotating better. Just be aware when you take the cover off the mag that the spring and ball doesn't pop out as they're very small. I'd try that 1st before doing anything with the indexing post and retaining clip if the rifle is new.