S&W barrels were threaded in and retained with a crosspin. Current barrels are merely threaded in with sloppier tolerances under greater pressure. This saves manufacturing time and costs. It also creates a distorted throat that can affect bullet accuracy. The swing out cylinder family of S&W first came with 5 frame screws securing the sideplate and cylinder yoke to the frame. Then they were reduced to 4 and finally 3 to reduce costs along with the barrel retaining pin. Earlier prewar pieces also have the 'long action' and higher hammer spur. Shooters complained about this and got a shorter locktime and lowered hammer. The irony is the older action is actually prefered by some shooters for accuracy and control. Aside from collectability, the screws are merely a signpost of production dates. A 5 screw is truly a handfitted firearm. The later 4 and earlier 3 screws still show good craftsmanship up until the bean counters and lawyers got involved. I owned a model 10 prewar with 6" barrel. I sold it to a good friend working with an armoured car service. He was so broke I loaned it to him to qualify for firearm carry. He shot a perfect score, as his Alabama grandfather would have expected and went to work carrying my handloaded 200 grain super police rounds ( another anachronism.) They got ambushed the first week. He put disabling rounds in both assailants before they had the shotguns on him <img src="/images/graemlins/blush.gif" alt="" /> Thats why I count my Smith screws so I don't <img src="/images/graemlins/wink.gif" alt="" />