Am I the only one that can't make one of these work. We have two of them and they are a constant headache. They are extremely hard to prime after installing a new cartridge, lose prime about half way through a cartridge and often times don't build enough pressure to put grease into areas that require a little more pressure. Have sent them back to Milwaukee and they come back exact same way they left. About $320 a set I would expect a little more.