Guys, I just wanted to write a quick follow-up on my strain screw post back in Feb. I took the x-frame out with the aformentioned FTX bullets yesterday. I tightened the screw all the way down. I'm still having some misfires. not as many as before, but it still happened several times.

How likely is it that a mainspring replacement fix this issue? If it's a probable fix, how hard is it to replace? I can order one from Midway and they're only a few bucks. Thoughts?

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Originally posted by Kingfisher:
Guys, I just wanted to write a quick follow-up on my strain screw post back in Feb. I took the x-frame out with the aformentioned FTX bullets yesterday. I tightened the screw all the way down. I'm still having some misfires. not as many as before, but it still happened several times.

How likely is it that a mainspring replacement fix this issue? If it's a probable fix, how hard is it to replace? I can order one from Midway and they're only a few bucks. Thoughts?

If you have a good Smithing screw driver set ,go for it.15 Min job.You dont want to bugger up your screws with household screw drivers.It is really no more than pulling the grips .Taking out the tensioning screw ,sliding the spring to the side at the bottom and taking it off the hammer.Reverse for assembly.

The .500 uses rifle primers if I am not mistaken. S&W did not make the mainspring strong enough. Even with the strain screw tight, it is not enough. I would look for a replacement spring.

Look for aftermarket springs like Wolfe, do not buy another S&W spring.

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The .500 uses rifle primers if I am not mistaken. S&W did not make the mainspring strong enough. Even with the strain screw tight, it is not enough. I would look for a replacement spring.

I have and have owned 5 S&W 500 Mag, and everyone of them fired each and every round. All my loads are with Large Rifle Primers, (Winchester). Except when the 500 Mags first came out all loaded with large pistol primers.

I have one S&W 500 Mag with over 2000 rounds down the tube, and not one fail to fire. I never heard S&W did not make the mainspring strong enough.
Actually the reason S&W recommended ammo makers and reloaders go to the rifle primer, was the pistol primers were getting pierced, and blow back was getting into the firing pin area and messing them up.

quote:

Originally posted by Kingfisher:
Guys, I just wanted to write a quick follow-up on my strain screw post back in Feb. I took the x-frame out with the aformentioned FTX bullets yesterday. I tightened the screw all the way down. I'm still having some misfires. not as many as before, but it still happened several times.

How likely is it that a mainspring replacement fix this issue? If it's a probable fix, how hard is it to replace? I can order one from Midway and they're only a few bucks. Thoughts?

I would suggest sending your gun back to S&W and have them replace the firing pin and check the gun over. Early on with the S&W 500 Mag , Smith & Wesson had a problem with some of the firing pins.

Thanks for the feedback gentlemen, I'll ponder what we've got here and make a decision. I may try replacing the spring before I send it back just because it's easy.

quote:

Originally posted by Kingfisher:
Thanks for the feedback gentlemen, I'll ponder what we've got here and make a decision. I may try replacing the spring before I send it back just because it's easy.

Question of the day.Are you using rifle primers???If you dont the Pistol primers seat deeper and will not always fire.

A spring is a spring and all are not equal. Some last forever and others don't. some are stronger and some are weaker.
I have seen too many springs take a set and weaken or shorten while others are 200 years old and still good.
I have seen springs snap in half and others bend, so yes, a bad spring can be in a gun.
Change it and see what happens.

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Question of the day.Are you using rifle primers???If you dont the Pistol primers seat deeper and will not always fire.

Yes, only LR primers, only LR primer brass.

Kingfisher; try first with a new spring, if this not fix the problem, take a look the firing pin how it protrude from firing pin hole (Mine S&W 500´s f.Pin protrude 0.05" (1,27 mm) from frame, maybe Your is a litle short, this happened to me with a S&W 617 .22 lr, a new firing pin will solve the issue, but I strongly recomend You, send it to S&W repair center. Regards Guille.

If you want to see if it's the spring just back it out and place a spent primer on the end of it and screw it back in. If the gun functions OK, replace the spring, or just leave it alone.

It could be the firing pin, or the spring or maybe even the strain screw could be a little short. It's anyone's guess unless you send the gun back.

I'm 98% sure it IS the spring. The gun was having misfires about 8 out of 10x the last time I took it out. Once I screwed the strain screw all the way in, it changed to about 2 out of 10. In short there was a marked improvement.

S&W might have mistakenly put in the wrong spring too. In a sixgun for LP primers the spring will be 22# to 23# but those made for rifle primers will be 28#.
I would guess the S&W springs are different too and the wrong one went into the gun.