My gun shoots too slow

This is a contest to help me fix a gun using the least amount of info from the owner as possible, inspired by many threads posted on the sub

All you get is “My gun shoots too slow” to start, if you can guess the proper fix you win.

If nobody can give the fix after a few hours I’ll poorly answer one question to hint yoi closer.

Edit: highest upvoted comment is the question I will poorly answer next

Edit2:

I would first check velocity and then check bps. Check O-rings and clean/lube marker. Then ask the owner wtf they actual mean haha

Orings clean and oil, speed is only 250 even though velocity is maxed out