21-4 light primer strikes?

Ugly Hombre

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I have a 21-4 that I like a lot, sad to say I started to get light primer strikes with the gun erratic misfires, sometimes 1 round out of a cylinder sometimes less often.

I took the grips off of it and tightened the main spring via the tension screw- still getting misfires.

Any idea what could be causing it? I know its not easy to say with out seeing the gun. I had stored the gun away for a while and the problem started after I took it to the range after a lay off.

Thanks for any ideas or direction-

Cheers!

U/H
 
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When you say you tightened the mainspring that presumes it was loose - was that deliberate or just happened?

Any gunk where the firing pin & hammer hit the frame? Under the extractor?

Check to see that the strain screw hasn't been shortened or the mainspring thinned on either side. Or replaced with an aftermarket lighter one.

FWIW, little trick I've used is to put an expended primer (with anvil popped out) atop the strain screw, if it's been modified. Gives a bit more length to the strain screw. An OK short term fix. Used it on an old Model 58 I just bought wherein someone had shortened the strain screw to such an extent the mainspring was a bit flat and put some resistance on the hammer cocking in SA mode.

FYI, Smiths evidently now use different strain screws for round butt or older square butt.
 
Thank you Sir,

*When you say you tightened the mainspring that presumes it was loose - was that deliberate or just happened?*

I bought the gun used, I checked on the internet for a possible fix that's why I tightened the main spring, trigger pull did not seem to light-- after I tightened it it was harder but not unduly heavy

*Any gunk where the firing pin & hammer hit the frame? Under the extractor?*

No looks clean will check again

*Check to see that the strain screw hasn't been shortened or the mainspring thinned on either side. Or replaced with an aftermarket lighter one.*

Very good advice will take the gun to a gun smith friend of mine later this week have him check this out, watch him and try to learn

*FWIW, little trick I've used is to put an expended primer (with anvil popped out) atop the strain screw, if it's been modified. Gives a bit more length to the strain screw. An OK short term fix. Used it on an old Model 58 I just bought wherein someone had shortened the strain screw to such an extent the mainspring was a bit flat and put some resistance on the hammer cocking in SA mode.*

More good advice never heard of modifying strain screws, I can't fix squat can only break things working on correcting that in my old age.

*FYI, Smiths evidently now use different strain screws for round butt or older square butt.*

Ditto more good info and advice thanks!

Addendum- I took the grips off this morning 12/7/20 and tightened the strain screw again- maxed it out, then off to the range to test fire, I figured I would shoot three cylinders worth at a steel pop up target and see how many misfires I got. I got none- wow happy camper! Put up a target and shot the left over 32 rds at paper at 12 yards. The gun is very accurate, I'm not a good shot but this .44 will sure put them on target- if I do the work.

Main spring and strain screw looked original, no gunk on firing pin under extractors etc.. The grips are not original though, they are eagle S&W repros. Did not notice that before.

Will go out to the range and back off the screw a bit- fire another box of shells and check if I can lighten up the trigger pull a bit- its not bad- little lighter would be good though.
 
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