I have an issue with my Smith and Wesson 610-3 competition revolver. It is an N-frame that was adapted to an internal firing pin by Smith at the request of IPSC, IDPA, and USPSA shooters in 1998, instead of the hammer-nose like you would have on a Model 29 or 28. It is a 10mm wheel gun with a non-fluted cylinder, uses moon clips to hold the rimless cartridges. I generally shoot .40 S&W instead of 10mm because the slightly shorter cases load and unload a fraction of a second faster and I can carry an extra moon clip loaded on each of the posts on my competition holster. The weapon lite-strikes and bangs two sometimes three rounds per cylinder. The shooter I got it from, loaded Federal small pistol primers exclusively, as is pretty typical among serious USPSA shooters in the revolver division because they are a bit higher domed and positive to ignite. I have loaded Federal primers, didn't help. I replaced the main spring, that didn't help either. I noticed the mainspring tension screw had been shortened and think this may be the problem. I am running double-action with it at 3.2 lbs and the mainspring tension screw is bottomed out. I ordered a replacement mainspring tension screw from Numrich today and believe this may solve my problem around 4 lbs. I really don't mind if it increases to 6, I have really strong hands and I am not that serious about the competition any more and want the thing to go bang every time the trigger is pulled, regardless of the primer that I am using. I am not very knowledgeable of N-frames, but I have been inside this one to swap rebound springs and mainsprings and I have good schematics. I just want to hear advice and comments, I know enough about gunsmithing to recognize a viable solution if the tension screw replacement doesn't solve the problem and am guessing it will be the firing pin replacement next? It is an excellent competition revolver but is now out-phased by the 8shot 9mms so I want to return it to fine tuned but within factory specs. I will load 10mm and use it primarily for hunting hogs.
I believe your on the right path, light strike wise! I would also look at the firing pin overall length, it may have mushroomed and had the burr ground off as a bandaid instead of replacing it! Last, I would check mainspring tension with the short nd old screw and again with the new screw. If the new screw changes tensin more then a pound, I would replace the spring and then adjust the tension screw down to get 4 to 5 pounds! In would Also consider the hammer it's self, has it been thinned, bobbed, or otherwise lightend? If so, you may not have enough inertia against anything but soft primers, you can test this against some different primers in your reloads and see it the issue clears it's self up? Again, a bandaid, but will help narrow things down a little bit! My self, Tully Mars, and Velsey ( if he shows up here in time to help) can help you further along if needed!
The firing pin is definitely on my list. The gun was lightened to function soley with federal primers and so finely tuned. I realize it is not ordinary to take a highly tuned competition revolver and make it a shooter but the action is sweet, the weight perfect and it is a fast gun! I want to carry it while hunting hogs in this damned underbrush. I think I can get it on picture as fast as a carbine or shotgun, 10mm is a man killer so should do just fine with pigs, I just want to make damned sure it goes BANG every time I pull that switch with my bugger picker.
You might also try another type of primers... I had a similar issue with one of my colts. Changed mainspring and checked another type of primers... it was primers one type was harder than others... changed main spring corrected the issue with all primer types... (2 coils had been removed from the spring to lighten the pull). action was also stoned, honed, jeweled and a few more tricks... still shoot like a champ... current trigger pull approximately 2.8lbs (haven't checked in a while and my memory is not as good as it once was)...
N-frame mainsprings are leaf springs with a screw that puts tension against the leaf. It is too sweet a pistol to retire but obsolete as a competition revolver due to the new 9-shot 9mm S&W pistols. They won't make major but who care in revolver division when you only have to reload half as many times? It will probably end up being a range gun but I'll still shoot it USPSA once in a while just because it is so much freaking fun.
Check the strain spring and tighten it if someone backed it off to lighten the trigger then shooting may have loosened it . Also see if the spring has been "knuckled" if the spring was too relaxed....
