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Old 11-12-2012, 10:29 AM
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Default ? About Replacing Revolver Mainspring

I have two Smith & Wesson model 19 revolvers. One is a 19-3 and the other is a 19-5. The 19-3 performs perfectly with my handloads using CCI primers, but the newer 19-5 will fail to fire about 2 or three rounds out of 50. The primer strike appears to be light on the rounds that fail to fire.
I bought the older gun new way back when, but the 19-5 was purchased used, and I am not sure if any mods were made to it. I have looked into installing a Wolff mainspring, but have questions. I have no experience working on revolvers, so I am not sure what is involved in replacing the mainspring. Is this something an amateur like me can do, and if so what do I need to watch out for? Do instructions come with the Wolff kit? And finally, do you think a new mainspring will solve the problem?
I realize that CCI primers are thought to be quite hard, but I have a lot of them, and I want the revolver to reliable with any ammo.
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Old 11-12-2012, 10:52 AM
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I have no experience working on revolvers,
No instructions come with new springs, so the first step is probably to learn enough to understand how the revolver works and try simple things first. Changing a mainspring ona K frame can be done just by removing the grips, but first you need to check that the strain screw is original and fully tightened. The Jerry Kuhnhausen "The S&W Revolver Shop Manual" is an excellent book.

Most people put in a Wolff reduced mainspring to REDUCE the trigger pull, and some cut or loosen the strain screw. These actions can cause light strikes, especially with some primers.

My IDPA revolver has the strutted reduced mainspring and requires that I use Federal primers. The double action trigger pull is about 7#.
It sounds like what you need is a stock S&W spring and a stock S&W strain screw to insure 100% reliability with your CCI primers. Or, it is possible you have a firing pin problem.
Instructor, CRO, CSO
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Old 11-12-2012, 11:07 AM
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Make sure the strain screw is tight on your current mainspring. I don't know if Wolf has directions or not, but I've removed and replaced them for complete disassembly of the internals. Not hard, remove the grips, then unscrew the strain screw until the mainspring is loose, the screw does not need to be completely removed from the frame. The spring can then be slipped off the stirrup on the hammer. You can then slip the new spring's end onto the stirrup and back in the butt of the frame and tighten the strain screw. I have done this without removing the side plate from the frame, it's a little tedious, but easily done. It's easier if the side plate is off, but don't do it if you're not comfortable doing that. Hope this helps, but unless the mainspring is broken, many times the strain screw isn't tight or someone has shortened it in an attempt to lighten the trigger pull, causing the light strikes you are experiencing.
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Old 11-12-2012, 02:17 PM
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If the strain screw has been "shortened" to lighten trigger pull, a quick "temp" fix is to take a spent primer, and remove the anvil part and loosen up the strain screw enough that you can slip the "cup" over the end of the screw and re-tighten fully. This just adds maybe .025" or so. If this helps , order a new full length strain screw.
H Richard
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Old 11-16-2012, 05:45 PM
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If you are restricted to only CCI primers you'll have to run the springing not much less than stock and a full strain screw cranked in tight. I would just run it with the stock spring and after all of those nasty CCI primers are gone install a lighter mainspring and start using Federal primers. Trust me, once you try a light S&W action with Federals you'll never go back. You do have to have to seat the primers ALL THE WAY in the pockets. Using Federal primers has given me 100% ignition on all of my revolvers for many years, and they are all set up with light springs.
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Old 11-16-2012, 11:05 PM
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A full length strain screw and original spring will bang CCI primers every time. First check is to make sure the screw is turned all the way in. If it is loos turn it all the way tight, and that should cure the issue. As most already fire, as little as a quarter of a turn could make the difference. Non the less, turn it all the way tight. It that does not fix the misfires, check to see if the screw has been shortened. If it looks like it has been filed, replace it. That should fix your problem.
Richard Gillespie
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