What is the strain screw for???

buttsm

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I recently purchased a used 625 JM, and in the parts box was a baggies labeled strain screw. What is it for, and what does it do? Should I reinstall it?
Thanks
 
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The screw loads the mainspring. Sounds like you have some of different lengths, which by a process of trial and error; would allowing you to get as light of a trigger pull as possible while still having 100% ignition.
 
The strain screw is located in the front of the frame grip, about behind your ring finger. If you revolver has trouble with misfires, the mainspring and/or your strain screw are probably not stock.
 
It's the screw on the bottom front of the grip frame that tensions the mainspring. It's supposed to be fully tightened. Loosening it or using a shorter strain screw will lighten the trigger pull but could also cause light primer strikes. Additionally, if you are loosening it on purpose, it can loosen even more after repeated firing and cause light primer strikes.

Keep it tightened so it won't back out on it's own and keep it at factory specs.
 
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Loosening it gives the gun a great trigger pull and misfires as well. But a great trigger pull. Mine came with the screw backed out and about a 5.5 # double action pull. It barely set off federal primers. I have no idea what the previous owner was shooting.


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When I first got my Model 625-9 revolver, it would occasionally not fire. It was the strain screw. It was too loose. Tightened the strain screw--no more "fails to fire" (FTF).

God bless,
Birdgun
 
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A loose strain screw is bad, but one that was shortened a bit and then installed tight is fine if the person who shortened it only took off enough to get a better trigger pull and still fire every round. Some (me) do this instead of installing reduced power spring. If your gun fires every round fine. If not try the spare screw, but always keep either tight as firing and recoil will cause a loose screw to slowly get looser and give you misfires.
 
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