Model 34 Fail to fire - any suggestions?


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cpirtle
September 9, 2007, 08:18 PM
Hey all, I have an early 2" model 34 that I recently picked up that has 1-2 failures to fire per cylinder when fired from DA mode. When I hit them the second time they fire and when I run the gun in SA mode it always fires.

I was thinking new springs were in order but if anyone has suggestions I'd appreciate it.

The gun looks to have had less than a few hundred rounds through it and I don't think it's dirty, but I'm open to suggestions.

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The Lone Haranguer
September 9, 2007, 08:35 PM
When the hammer is cocked for SA fire, the hammer falls a longer distance and there is more tension (stored potential energy) in the mainspring, so the extra impact is enough to fire the cartridge, whereas in DA it may not. It may need a new mainspring. It would have to be totally "gunked" or rusted up inside to retard the hammer fall.

Brian Williams
September 9, 2007, 09:47 PM
I have a 35-1 that will FTFire if the charge holes are not clean.

The Lone Haranguer
September 9, 2007, 10:15 PM
Is that because fouling buildup keeps the cartridges from fully seating and cushions the firing pin blow?

cpirtle
September 9, 2007, 10:37 PM
I was planning on checking that tonight, but this gun was EXTRA clean, so I wold be surprised.

My first thought was the mainspring but I want to make sure I'm not overlooking a common problem before ordering the spring.

esq_stu
September 9, 2007, 10:42 PM
More used revolvers I have bought than I can count have had cut/weak main/hammer springs in order to lighten trigger pull. And they also fail to fire more than is acceptable. On an old revolver, I often go right to Wolff (or the factory if they're still made) and buy/install new factory strength springs - the problem usually disappears (usually).

mec
September 9, 2007, 10:44 PM
Several possiblilities aside from those already mentioned. Some k frames/frame mounted firing pins are a bit shorter in the pin than optimum. this plus a small amount of end float can cause misfires-particularly with cci rimfire ammunition as it is a bit thicker in the rim than other rounds. I had a k22 that Hamilton Bowen adjusted when it would not set off cci s double action.

One fix might work though it is fairly tedious. Remove the coil mainspring from the strut, put a washer under the spring on the strut and reassemble the whole thing. Take care that the spring doesn't launch and stick a hole in you.

mnrivrat
September 10, 2007, 12:48 AM
Put in a new hammer spring .

VA27
September 10, 2007, 01:33 AM
I picked up one that acted just like that. What I discovered was that the hole in the firing pin bushing was oversize and allowing the firing pin to slide up and off of the cartridge rim. I ordered a new firing pin, firing pin spring and bushing from Gun Parts and it shoots 100% now.

Master Blaster
September 10, 2007, 08:28 AM
.22lr uses a heeled bullet, meaning the diameter of the bullet is larger than the case, and it sits over the outside of the case. This means it leaves more residue in the cylinder where the bullet touches the cylinder, than a centerfire. The buildup keeps rounds from seating fully, so the firing pin's first blow seats the round resulting in a light strike.

Clean the cylinder out real well with a brass brush, also you may have better luck with federal copper plated ammo, that doesnt have the wax lube.

cpirtle
September 11, 2007, 03:55 PM
Just thought I'd update on the outcome.

The previous owner had installed what would appear to be a lighter Wolff spring.

Since the gun was a local Gander Mountain purchase ($300 :D )I took them up on their 1 year used gun warranty. Called their smith this morning, he had a factory spring on hand so I swung in one my lunch and he changed it out in about 5 minutes, test fired 12 shots DA and it ran fine.

I should have known the PO did something to the spring, the gun showed very minor signs of being opened when I got it and it had a trigger shoe on it. Still can't figure out why someone wanted to turn a 2" revolver into a target gun.

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