Been greasing things with zerts most of my life. Yes, loosening the tip will help, but I don't like that way because it also leaks out and makes a mess. The whole trick is in the nipple. There are three little collars that under pressure, lock onto the zert head. After you grease the pin, shove the nipple onto the zert harder and maybe twist a little. That will releave the pressure and allow the collars to release and you can pull it off. The newer the nipple, the tighter the grip.