Model 36 Fails to Fire!

[dubious]

I've got a classy old model 36 from the early 70s which fails to fire a lot more often than I would like. I replaced the spring with a standard power 8lb (edit 8.5lb) wolff spring and it still failed, so I bought a used DA only hammer. It STILL fails to fire, especially magtech and not so much with federal. Now I've just installed a 9lb extra power spring. I haven't tried it yet, but if it doesn't work, what's the next logical step? Isn't a 9lb spring overkill for a gun that looks really clean and rust free internally?

Thanks!

 

[Boogsawaste]

Does it have endshake?

Edit: excessive endshake will cause the cylinder to be able to move closer to the barrel and farther from the firing pin causing light primer strikes.

 

[dubious]

No, it's very tight. Tighter than my Model 19. Great question though! EDIT: I double checked and it has very little end shake. Also i can't isolate it to any particular cylinder. It seems random.

 

[bettis1]

Have you tried different brands of ammo to rule out excessively hard primers?

Bob

 

[dubious]

2 boxes Federal is like 95% and 2 boxes of magtech 158 gr LRN is about 60% reliable. That's it so far. It's hard to find 38 special these days!

 

[gsm73]

The 8 lb Wolff spring is a reduced power. I believe factory spring is around 12 lb.

 

[dubious]

Actually I went from 8.5lb to 9lb... this is from Wolff Gun Springs:

Reduced Power...: 8 Lb.
Factory Standard.: 8.5 Lb.
Extra Power.........: 9 Lb.

SMITH & WESSON J FRAME REVOLVERS
Includes Models: 31, 32, 34, 36, 37, 38, 42, 442, 49, 60, 63, 631, 632, 637, 638, 640, 642, 649, 940.

 

[gsm73]

I see that on their site. Well I got out a 36 no dash from mid 70's and went back and forth between the factory spring and the Wolff 8 lb and there is quite a bit of difference between the two. Mine did not like the 8 lb spring either and I currently use the oem spring. I have had good luck with the Apex kit in a 642 but that will not help with guns that have hammer mounted firing pins.

 

[STCM(SW)]

How about trying a different hammer?

 

[dubious]

How about trying a different hammer?

I have tried both a SA/DA and DAO hammers. Neither works well.

 

[ShelbyV8]

I have never saw anything on it, but it sounds like there may be a difference in the springs between the the hammer mount and the frame mount firing pins.

Sent from my DROID BIONIC using Tapatalk

 

[Waywatcher]

Thinking out loud:

Maybe it came from the factory with excessive headspace?

Firing pin out of spec?

Those are the only two that come immediately to mind. If it doesn't even fire Federal 100%, there's definitely something not right. Since endshake, hammer and mainspring are ruled out, that leaves headspace, and firing pin deficiencies. I am even doubting the possibility of a problem with the firing pin.

 

[gboling]

Have you actually checked the weight of the trigger pull with a gauge?

At the factory the strain screws are custom fit (shortened if necessary) to attain the proper weight of pull. One of the popular, trigger jobs, by Bubba gun smith is to lighten the trigger pull by shortening the strain screw. Weighing the trigger pull would tell much.

 

[gsm73]

Have you actually checked the weight of the trigger pull with a gauge?

At the factory the strain screws are custom fit (shortened if necessary) to attain the proper weight of pull. One of the popular, trigger jobs, by Bubba gun smith is to lighten the trigger pull by shortening the strain screw. Weighing the trigger pull would tell much.

J frames do not use a strain screw.

 

[cochise]

You mentioned you changed springs. An after market "light" spring is known for causing mis fires. I would go back to a factory spec spring and check for reliable ignition.

 

[Waywatcher]

You mentioned you changed springs. An after market "light" spring is known for causing mis fires. I would go back to a factory spec spring and check for reliable ignition.

No, he replaced the mainspring with a factory weight spring.

 

[beagleye]

Can you check the firing pin protrusion?

How do the primers look?

 

[armorer951]

Can you check the rear gauge......distance between the back of the cylinder and the breechface? Should be between .060 and .064.

 

[Waywatcher]

Can you check the firing pin protrusion?

How do the primers look?

I'm thinking it's not a firing pin problem because he has tried two different hammers (and thus two different firing pins.)

Obviously we can't completely rule it out, but it is lower on the list I think.

At this point, I'd like to know what the headspace is measuring. It will take some feeler gauges; but at the least it could rule it out or in.

 

[dubious]

Yep... I just uprgraded from standard 8.5lb to an extra power 9lb spring which i still can't try until tomorrow. Two different firing pins on 2 hammers which look pretty good. Primer indents LOOK pretty normal on the misfired rounds. I'm pretty sure upgrading the spring weight will do it. I'll report back!