I've got 2 pistol grip grease guns. One of them I bought new at the local farm store, the other one came from a farm auction. The old one works perfect. The new one never did work quite right. A full stroke of the handle equals about 1/2 of a stroke.
The rigid pipe can easily be removed and a flexible hose installed. The flexible hose comes in many different lengths. I've seen up to about 4 feet in length.
I've been using grease guns for probably 50 years now, and I know the little tricks needed to get the air out. Some of these new grease guns just plain don't work.