I have had one now for a couple years, the gears are definitely plastic.
Many have complained that the gears easily break, but I've been extra careful with mine and, so far, I haven't had a problem. You must be especially careful when the piston bottoms out or when stuffing small diameter sausages.
But, no doubt it's the best value in a stuffer, IMHO!
The LEM 5 lb. stuffer has metal gears and the Grizzly can be retrofitted with gears from LEM if the Grizzly gears ever break. That's my plan of attack!
Here's a link to LEM for the gears....
http://www.lemproducts.com/product/1470 ... ffer_Parts
Here's a good video review (not mine) of the Grizzly stuffer....
http://www.youtube.com/watch?v=iunQ1mBfzdg