Looking for a reliable hand held grease gun to do my tractor, mowers, etc. Have gone thru two already, the $20 variety, and both simply don't function reliably. The one I try to use now has a good relief valve on top but that really doesn't seem to help. I get it going and half way thru it stops. Aggravating is way too mild a word. I looked at one at Tractor Supply yesterday for about $35 that looked well built, but not sure its any better. Do the compressor powered gease guns work any better? I'd go that route if I could be confident of it, but hate to spend the money. Are there any such things as a reliable grease gun?