model 34-1 double action issue

[Bob Matzka]

I have a 34-1 kit gun that has an intermittent issue when firing double action. The double action works properly with no cartridges in the cylinder. When loaded with new cartridges is has intermittent hang ups after firing. Sometimes occurs with the first round fired other times on firing subsequent rounds. when the hand up occurs manually cocking (hard) completes the cylinder rotation so it can be fired. Once all cartridges have be fired the double action works normally with the fired cases in the cylinder.
It seems something in the firing process is causing the hang up
Cleaning between loads sometimes helps but that is inconsistent also.
Note: this is a Kit Gun with 4" barrel (SN 490262) I purchased used a few years ago to have an inexpensive pistol for practicing double action. I have 2 other S&W revolvers a model a Model 36 and a model 10 M&P Both of those work just fine.
Has anyone else experienced this issue.

 

[austintexas]

Hang up

Sounds like some cartridges are not seating all the way in the chamber. It shouldn't cost much to have a gunsmith run a finish reamer in the cylinder charge holes and free them up a little.
SWCA 892

 

[Protocall_Design]

Check for a burr around the firing pin hole. A fired primer can hang up on a burr. If there is one, it can be stoned or filed flat, thereby removing it. There may be something else at play, it's hard to know without seeing the gun.

 

[Bob Matzka]

I have cleaned the cylinder bores with a stainless brush the cartridges fall free going in and freely eject when fired.
Have also check for burs around firing pin hole and checked firing pin retraction. No burrs and pin retracts below flush.
Also cleaned the seats for the cartridge rims to insure they seat flush. Cleaned both sides of the extractor to insure is is also seating flush in the cylinder. Have disassembled the cylinder extractor mechanism looking for possible burrs, fouling, etc. ot no avail. I have examined the fired case rims for raised burrs and even used a feeler gage to check the gap between the cylinder with fired cases and the firing pin face to see if it is binding. The cylinder rotates freely.
I have removed the side plate looking for an possible timing issue but could not identify anything. It all seems to be workijg properly.
This is a really frustrating problem so looking for anyone who has experienced this with the rim fire pistol.
Thank you for taking time to respond

 

[M29since14]

It sounds like your problem is ammunition related, not gun related. I’d say try several different brands of .22s.

 

[CalifEd]

Just a thought, is the hang up with the cylinder not rotating smoothly or with the hammer binding when doing DA with a live cartridge in the cylinder.
Is it hanging at the same spot/cylinder each time?

If you have checked the cylinder gap and end shake check that the yoke and cylinder are in alignment.
Open the cylinder and spin it. Watch to see if the extractor rod wobbles at all. If you can see any wobble, get the yoke back in alignment.

Take a feeler gage and check cylinder gap and head space on each cylinder, especially if the hang up is at the on the same cylinder each time.

 

[daveboy]

When I was a teenager, I had the exact same problem with my dad's Colt Frontier. Everything worked fine when dry-firing. When I actually fired it, the cylinder would often be hard to turn, sometimes locking up the gun.

The answer turned out to be very simple. It was oil in the chambers. Cleaning all oil out of the chambers solved the problem.

Normally, when a cartridge fires the brass expands and grips the walls of the chamber. Some of the rearward force applied to the cartridge is transferred to the gun because of this tight grip between the cartridge and chamber. A coating of oil between the cartridge and the chamber will not allow this grip to take place. Oil does not compress, so the cartridge can't get a grip. Therefore, the rearward force on the cartridge is all applied to the base of the cartridge, which pushes it against the firing pin/recoil shield.

Make sure the chambers are squeaky clean.

 

[Bob Matzka]

Thanks again I appreciate all your comments.


the hang up does not occur at the same cylinder every time.

I have checked gaps with a feeler gage before and after firing. Also examined the fired cases for raised burrs.

I will explore the end shake.

I Will try some of my premium CCI ammo. Have been using inexpensive bulk ammo but from reliable manufactures.

I do clean the cylinder bores so the new rounds drop in flush brush around the extractor to be sure it is seating.

Bob Matzka

 

[Protocall_Design]

You might check to see if the tip of the hand is sticking out past the recoil shield when you pull the trigger. You can check this with the cylinder open and while holding the thumb latch back.

If it is, it can catch on the rim of a case, and make it hard to pull the trigger. The fix is to file the hand nose back to flush with the recoil shield. You will need a diamond file or grinder for that operation.

 

[Alk8944]

^^^^^^ Protocol Design's assessment is 100% correct. This may not be the issue, but it is very likely to be! The hand cannot protrude past the face of the breech! If it does it will cause anywhere from just a slight "catch" when cocking to being impossible to cock the gun, depending on how much too far it protrudes and the caliber of the gun.

I have fixed revolvers with the same problem as OPs and this was what caused it! This includes my own 4" Model 12. That gun was so bad that the gun couldn't be cocked when loaded but worked just fine when not loaded. I have never figured out how it ever passed test-firing on the range before final inspection!

And, BTW, Revolvers have only one cylinder. That cylinder contains several chambers, also referred to as "charge holes".

 

[Mike SC Hunter]

Also almost "unseeable" dirt can get under the extractor and in the extractor cut on the cylinder. Causing the ejector to sit slightly proud of the cylinder causing binding.

 

[Bob Matzka]

Problem solved

The last post regarding the Hand turned out to be the problem
I have two other S&W revolves older 38 special one J frame snub nose and one model 10, On both of those the hand is flush or slightly below flush the shield face. on the 22 cal. kit gun the hand was protruding a above the shield surface. I removed the hand and filed the nose down (yes a diamond file was needed) so it is flush. I was able to cycle a half dozen full cylinders through rapid fire without the the bind.
I knew there was someone out there who could lead me to a solution.
Bob Matzka