I had one of these a while back but returned it to my local dealer with nails under 1" long due to frequent sticking and constant misfires. I needed a nailer for another project and since I have a full set of Ryobi One Plus tools I ordered this refurbished one. This one seems to be more reliable than the new one I had before. It still fails from time to time, but I ended my project with a few problems. This tool came with a lightly greased combustion chamber (if I'm using the correct term), which I don't think was the case with the first one I had. Lubrication makes the tool more reliable. Subtract 1 star for random misfires.