I've got a 4566, and took it out to the range two weekends ago and tossed about 200 rounds down range. At the time, double action shooting was working properly, although with fresh magazines I'd shoot the first round by pre-cocking the hammer to shoot single action(?), so I wasn't shooting double action on the first shot. (Sorry if the terminology is wrong here, still kind of new to shooting).

Anyhow, playing with my snap caps today and working on trigger pull I noticed double action wasn't working at all. See below:



These images are here just to show the gun was loaded with a snap cap and a snap cap only.


As you can see, I barely pull the trigger back but it doesn't engage the hammer like it normally would.

This isn't normal, is it? Previously if I pulled the trigger on the first round without first pre-cocking the pistol it'd engage the hammer. Now it doesn't.

How can I fix this?

Thanks for the help / any info you can give me.

Are you using S&W factory magazines? I had this happen with a 457 and traced the problem to aftermarket magazines. For whatever reason, they weren't disengaging the magazine safety in double action. They worked fine in single action.

Even if you are using a factory magazine, you might try a different one, just to make sure that the magazine isn't bent and is causing the problem.

__________________
Can open, worms everywhere.

You're the man!

Look at the image below. Take a guess at which one is the bad magazine



Both are factory mags, but one is slightly cracked / bent. Never looked at them that closely. Put a snap cap in the other magazine, DA worked as it was supposed to.

Looks like I'll be ordering some new magazine when I find some.

Don't go thinking I'm that smart! It took me a couple of hours of playing with magazines to finally figure it out. When I bought the 457 I got seven magazines with it. Five were OEM, two were aftermarket. Only after putting them side by side did I notice the difference. I know better now, which is why I never buy aftermarket magazines and test fire all magazines before I put them into a firearm I carry for self defense.

I'm glad you figured it out. There is nothing more annoying than a gun that won't fire when you want it to.

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Can open, worms everywhere.

Haha, well I'm glad it was an easy thing to diagnose. The gun was purchased second hand and this was noticed after my first time at the range with it (prior to this I had only fired 8 rounds through it elsewhere). I was worried someone sold me something with issues. Glad it's just the magazine!

Glad it was just a mag problem.

This is a good time to point out that despite the cost magazines ARE a disposable item. Use them and throw them away when they get worn out.

Interesting timing too, as I'm about to replace the magazine on a 40+ year old Ruger Standard pistol that stopped feeding rounds properly. So going to try to pick up two new ones to replace the only one I have that is failing, and might as well pick up 2+ new S&W magazines too. Will wait till next payday though, my gun allowance this week just got spent on a Galco IWB holster for a Sig 220/226 (hopefully will work fine with my 4566TSW) and a gun belt. =]