RNeumann
Elite Member
google "injector grease gun"
HF used to sell something like Dualco Grease Gun With Short Nozzle > Accessories > Tools & Maintenance > Grease | Jenson USA which I use.
I'll second this type- maybe not model. I had the best luck locating what you are looking for a the bike shops. Jenson, Arts etc will be sure bets.
Btw they make a needle zerk fitting if you wanted to use your tractor grease gun.