S&W problem w/double action

[The Pogo]

Got a Smith K400 66 stainless. Sure fire on single action every time but misfires at least one in every load firing double action and often 3 or 4. Tried 38 spl, spl+p &357mag and in different brands, same problem. Has Pachy grips and grip screw SEEMS to interfere with mainspring (Damned hard to line-up) I wait a minute after the misfire and unload and fire the "duds" single action and they fire. Any ideas out there.....please?

[Dale53]

On an S&W, the hammer falls further and hits harder when used single action. Double action shortens the hammer fall and reduces the hit.

I suggest you increase the weight of the mainspring (use an original spring) to increase the hammer hit. Sometimes it is nothing more than the main spring screw has backed out reducing the force of the main spring.

Dale53

Dale53

[The Pogo]

Thanks Dale; That's kinda the way I was leaning but didn't want to start with the screwdriver without another opinion. The Pachmayers still bother me a bit, that screw is right between the spring and the frame.

The Pogo.

[imashooter2]

A well known problem with Pachmayer grips. I don't think that they interfere with the spring once installed, that is what the necked down section is for.

An old trick is to put a used primer cup over the end of the strain screw for a bit more tension.

[bobthenailer]

i have seen the mainspring screw in the front of the grip frame back out ! on mine and several others over the years ! its a common problem , just add a little blue lock tight to the screws threads! i ck it first ! odds are its loose

[home in oz]

How do you know it is tight enough?

Turned in flush?

What are the guidelines?

[ReloaderFred]

The strain screw on S&W revolvers is designed to be screwed all the way in. When the screw bottoms out, the proper tension is set on the hammer spring.

Was this a used gun, or new? Many people do "kitchen counter" action jobs by either backing out the strain screw, or grinding some off the nose of the screw. Backing off the screw is a bad idea, and if you don't know what you're doing when grinding off the nose, it's an even worse idea. Some people also attempt to lighten the trigger pull by grinding the sides of the hammer spring, or of slimming it down. I've seen some real butcher jobs on those springs.

The bottom line is to make sure the strain screw is in tight before you do anything else. If it's in all the way, then you'll have to look at the length of the screw and the other areas I've mentioned above. Hogue makes some great grips for S&W revolvers, as do many others.

Hope this helps.

Fred

[home in oz]

A used gun.

I will take off the grips, and screw it all the way in.

Thanks.

[The Pogo]

Guy I bought the S&W from bought it new and knowing him it had never been cleaned except with the bristle brush that came with it, much less attacked with a screwdriver or stone. The mechanical concept of the pocket knife was beyond him. Any road, I loosend the Pachys and located the screw in question and took it down flush with the frame. Problem solved!
Concerning the hammer travel DA vs SA, I'd never thought about it before but I got out my protractor and sure'nuff it travels 12 degrees farther on SA! Many thanks to all. Now, about my Girlfriend.....................................

[Freightman]

Now, about my Girlfriend.....................................
Your problem, not anyway an expert on the girlfriends I have been with mine (wife) 50 years and she still confuses me. By the way welcome to the board, saw your pet on my fence the other night!

[Dale53]

The Pogo;
Now THAT is what we like to hear (problem solved)!

Dale53

[Dill45]

I had a similar problem with a 500. Came from the factory with a light hammer strike. The screw was flush, but it was still light. I ended up putting a small shim between the screw and the spring to give the screw a little more length. Took care of the problem, but boy does one have to be careful when lowering the hammer in a controlled fashion. (Maybe to hard of a hammer fall now :( )

[Dale53]

You will need to check to be sure (I am away from my workshop) but I believe that the screw size is 8x32 (someone can chime in here). You can get a stainless screw from your local hardware store and fit it too length that gives you the hammer fall you need or prefer.

Dale53

[casterofboolits]

The great thing about this site is the willingness of all members to help every one. I have not seen a problem go unsolved.

[The Pogo]

Gee Freightman, that's not my pet, that's me and it's a long walk from the Okefenokee to your fence! Thanx for the welcome. I married mine in Nuremberg on the 12th anniversary of D Day. We've done our best to keep peace from breaking out. This was my first foray into a forum...the response has been amazing. And again thanks to EVERYONE for the support.

[Lloyd Smale]

Like was said check the tension screw as ive had them back off. Also for the most part i use federal primers on any gun im going to use in DA mode. There alot easier to ignite even with light primer hits.

[MtGun44]

Hi Pogo -

What part of town? I'm near old town.

Bill

[countglockula]

The best way to make repeatable adjustments to the hammer spring is to go to the auto supply and purchase an inexpensive offset tappet gauge. To those unfamiliar with this device, it is a series of calibrated shims made of steel that are used to set the valve clearances on non-hydraulic valves. they are typically sole in a set, mounted in a metal framework with a screw in one end, so they can be used and stored without being lost.

Didassemble the device and you will have a nice set of calibrated shims that can be cut with a dremel cutting wheel tool to fit nicely between the frame screw and the mainspring. By varying the thickness of the shim, using the different shims available, you will easily find a thickness that offers the perfect hammer tension. Finish up by using blue Locktite to secure the frame screw and you are done.

A bonus is that the shim between the hammer spring and the screw distributes the pressure loading of the frame screw more evenly and helps prevent hammer spring breakage.

I have used this technique for many years and it has never failed. works well even for a butchered gun that has had part of the frame screw filed off.

Ron

[Old Caster]

Different Smith & Wessons have different lengths of mainspring screws and someone might have put in a shorter one or as said earlier, filed off the correct one in your gun.