I go through allot of grease and tried quite a few of the air grease guns. I started out with Lincoln, but after taking the first one back, and then wearing out the second one in about six months, gave up on them. I tried two different brands from Northern Tool. They worked OK, but neither lasted very long. I bought the most expensive one that Sears sold and liked it for awhile, but then it stopped working and was always getting air locked. The Napa gun never worked from day one, so I took it back. I'm no longer buying from Napa, but it's not just the grease gun, their parts are never the right ones, or they are out of what I'm looking for.
After years of fighting the air hose and wasting hundreds of dollars on air guns, I've given up on all of them. I'm sure there are those out there that work fine, but I go through three to six tubes of grease in a day if I'm working with my Dad and we're running both the dozer and backhoe. Old equipment takes plenty of lubrication!!!
Currently I have three grease guns that I'm using. All are manual. The Walmart one works fine, but it's not as good as the two from Atwoods. Both of those are their premium manual lever grease guns. I have one with a flex tube and another with the solid tube. The Walmart gun has the solid tube and tends to go out in the field when I'm leaving the tractor there for the night.
I prefer the solid tube over the flexible tubes. You don't have to hold the tube and it's allot faster then messing with the flexible tube. For the few fittings that I cannot get to with the solid tube, I use the other grease gun.
I've found that it's faster to just manually pump grease my fittings then it is to get the hose and mess around with air locks on the air grease guns. I won't buy another air gun now that I've realized that I was creating more work and taking more time to use them.
I'm curious about the cordless, battery powered grease guns, but wonder if I'll actually save any time with them, or will they also be a hassle to keep working like the air guns are?
I know allot of guys who will spend days trying to find a shortcut, or an easier way to do something. When it's a tough task that needs doing, I just do it and get it over with in a day or even a few hours. It's painful, but always faster to just get it done. The same is true with greasing fittings. Just grab a manual gun and get it done. They always work, never have air pocket issues and are simple to operate.
Eddie