I also have one of those old little brass grease guns. Works perfectly with a bit of rag over the business end to make a seal! I often also wondered why they were called "pom-pom". Well, it was 50 years ago and many of the users would have seen service in WW2 and seen plenty of guns in action. Maybe the telescopic action of the grease gun reminded them of the recoil mechanism of an AA gun.