I purchased mine back in 1966 when I purchased an MG which had grease nipples on the steering. Still have it for my disco now fitted with a flexi spout to make things easygoing around both props.
The Milwaukee grease gun has a little button you push to bleed the air out nice and easy to use, it is especially useful as some of the trailers I have to grease up use three whole cartridges of grease.