New to me 10-5, Light primer strikes and more ??'s

[Jason4x4]

Got this 10-5 in trade. Took it out to shoot, had 75% light primer strikes, wouldn't fire.

research shows tighten screw, and make sure main spring is flat.

Screw was Not tight, so I will tighten that once I get main spring issue figured out.

It appears to me the main spring is obviously Not flat, but what exactly IS flat? flat to the "hooks"?

Any more info on this gun would be handy, Serial # C855xxx, 3 screw

 

[amazingflapjack]

I think the strain screw not being tight is your issue.

 

[PR24]

You never know. I picked up a BEAUTIFUL Mod 15-3 for a song. When one of my agency's range officer checked it for dept specs, it was out of time on 3 out of 6 chambers! Closer inspection revealed that some idiot had messed with the lugs in the star & rounded the edges of the cylinder stop. Pissed hardly describes it!! The gun is damn near new but some ******* with more time than brains almost ruined it. An oversized hand helped the timing a bit but I'm going to have to replace the star & cylider stop it seems.

My advice re the M10 is take it to a qualified S&W armorer or gunsmith.

 

[jimbo728]

If tightening does not solve the mainspring problem, which it may, just call S&W and ask for parts. They will send you a new one.
Jim

 

[Jason4x4]

If tightening does not solve the mainspring problem, which it may, just call S&W and ask for parts. They will send you a new one.
Jim

Is that a warranty part?

 

[bananaman]

I had the same issue on 2 Model 10's. Screw was tight though. Screws on both were shortened. New screws= no more problems for me. Bob

 

[MajorD]

If tightening the strain screw does not solve the problem ( it will 90% of the time) a little trouble shooting trick is to loosen screw and take a spent primer ( with the anvil removed) and put it on the tip of the screw contacting the mainspring and retighten if problem goes away you can buy a longer screw for a permanent fix. I honestly had a k frame I did this to and just left the little primer cap on the screw and shot it for years that way

 

[jimbo728]

Is that a warranty part?

A courtesy part, in my experience. I requested a replacement, went to pay and they wouldnt take payment.
Jim

 

[VNK971]

Loosening or shortening the strain screw is how some people try to lighten the trigger pull. I tried to get a new strain screw for a square butt k frame, but they are next to impossible find. Plenty for round butt k frames.

 

[Sgt 127]

I have saved strain screws by chucking up the non threaded end in a drill and using a file, cut down the underside of the screw head so it would seat deeper. Kind of a makeshift lathe.

 

[Bpx4st]

Got this 10-5 in trade. Took it out to shoot, had 75% light primer strikes, wouldn't fire.

research shows tighten screw, and make sure main spring is flat.

Screw was Not tight, so I will tighten that once I get main spring issue figured out.

It appears to me the main spring is obviously Not flat, but what exactly IS flat? flat to the "hooks"?

Any more info on this gun would be handy, Serial # C855xxx, 3 screw

Not real familiar with the model 10s but the workings can't be much different than the 66. At least, I can show you what the spring should look like & another possibility.

In particular, part numbers (on 66) 7016 (the main spring) should look like this...about as flat as they are. What it could be, is someone tried a trigger job & may have cut a coil on the rebound slide spring (part 7028, again, on the 66) to try to lighten the trigger, causing the 7129 (for square butt, or 7228 for round butt) strain screw to be too short. If your main spring has a bow in it, that would compound the light strike problem. Unless you feel confident in taking the rebound slide assembley apart & putting it back together, I wouldnt try it cause it's tricky...but a new, heavier, rebound spring might help.
The main spring you show looked a little bowed which could indicate over compensation for a weak rebound spring. If a new one is freely provided by the company, I believe I would go ahead & get one just to be safe.

I downloaded my manual online for free & suggest if you don't have one, you do that for your model. They're very handy to have.

Wayne

Sent from my SM-T377P using Tapatalk

 

[raisedin99]

Give this a try:
terry

[ame]https://www.youtube.com/watch?v=WqmlI3FBvLE[/ame]

 

[jframejoey]

Jason, can you take the main spring screw out of the frame and take a picture for us? Leaf spring looks normal to me.

 

[Targets Guy]

I had a similar issue with a 1951 K38. The strain screw was loose and tightening it all the way in helped but still had a few misfires. The gunsmith found a broken spring inside. No problems after that.

 

[Jason4x4]

here is the screw, it appears to be a little mushroomed at the tip. I also followed the video and tore it down and cleaned and lubed everything

 

[VNK971]

I bought a 10-6, sn C836368, and had light strike issues. I took it apart and cleaned it, made sure the strain screw was tight, new standard main spring from Brownells, and still had light strikes, FTF. The problem turned out to be the firing pin/hammer nose wasn't moving the way it was supposed to. After about 50 years dirt and rust had gotten in the slot. Power Custom hammer nose kit solved the problem. It's on page 107 in the Kuhnhausen shop manual, 5th edition.

 

[H Richard]

That screw has been filed shorter. The originals are rounded on the end. A new original length screw should fix your problem. Call S&W make sure to give them the Model # you need the screw for it is called the Strain screw. Bpx4st has a parts list above.

 

[lefty_jake]

Jason4x4, do you have access to a trigger pull scale? The pull weight for the double action trigger gives a very approximate estimate of the mainspring strength, so it would be useful to know the double action trigger weight. For example, if the weight is below 7.5lb, then you probably need a longer strain screw, and if the weight is above 10 lb, then there probably is another problem. If the double action is between those weights, knowing it still might give some hints.

You can also use the trigger scale to directly measure the strength of the mainspring as shown in post #2 of this thread:

http://smith-wessonforum.com/s-w-smithing/441723-question-about-testing-hammer-spring-weight.html

If you need a longer screw, you should try the advice above from MajorD. Use the cup from a spent small primer as a shim on the end of the strain screw. This will give a good indication whether a longer screw will help.

If you have trouble finding a new strain screw for a square butt, there is a seller on ebay called "gun garage" who usually has them. I have no connection to this seller, and I have not tried their strain screws, but I know they often have hard to find screws in stock.

 

[Jason4x4]

thanks, ordered one from ebay

Jason4x4, do you have access to a trigger pull scale? The pull weight for the double action trigger gives a very approximate estimate of the mainspring strength, so it would be useful to know the double action trigger weight. For example, if the weight is below 7.5lb, then you probably need a longer strain screw, and if the weight is above 10 lb, then there probably is another problem. If the double action is between those weights, knowing it still might give some hints.

You can also use the trigger scale to directly measure the strength of the mainspring as shown in post #2 of this thread:

http://smith-wessonforum.com/s-w-smithing/441723-question-about-testing-hammer-spring-weight.html

If you need a longer screw, you should try the advice above from MajorD. Use the cup from a spent small primer as a shim on the end of the strain screw. This will give a good indication whether a longer screw will help.

If you have trouble finding a new strain screw for a square butt, there is a seller on ebay called "gun garage" who usually has them. I have no connection to this seller, and I have not tried their strain screws, but I know they often have hard to find screws in stock.