I have a 17-2 in really nice ( not collectible ) condition that is a joy to shoot at the range. Recently, the action began locking up after 15 to 20 rounds of .22lr (various brands-doesn't seem to make a difference). I took it home and cleaned it to perfection and the same thing has happened-twice. I took it to my local gunsmith and he could not get it to lock up, he cleaned it again at no charge and - no kidding it happened again. Same scenario. The hammer only moves a little and the cylinder won't revolve at all. This also occurs in double action. I can unlatch the yoke and all appears fine. Lock it closed and the actions just locks up. Clean it and it works fine until a few rounds are fired. Any suggestions? I am stumped!