For those of us with S&W Revolvers, especially older guns, I have found a must-have tool. With many of the older revolvers (I have a pre-10 M&P) you will find that you need to tighten the extractor rod more often and will need to keep the cylinder face really clean. This is due to the closer tolerances the older guns were made to, causing a really close cylinder to barrel gap. I have a nickel plated M&P from 1951 and the plating has taken the gap down to almost non-existent. I found that using a vise and padded pliers to unscrew the extractor rod caused a lot of binding and twisting of the rod, no matter how careful I tried to be. Brownells makes a S&W Extractor Rod Tool that allows screwing the rod in and out much easier and less trying. It is worth the money to stop the possibility of damaging the rod. I have one for my J-Frames and one for my K/L frames (the sizes are different) and wouldn’t be without them now. See link below.
BROWNELLS : BROWNELLS : EXTRACTOR ROD TOOL - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools