Model 10-5 problem.

[dakasat]

Gents,
I have a Smith Model 10-5 that works well in DA. When it is cocked for SA fire and the trigger is pulled, the hammer engages the trigger in some fashion and the trigger kicks forward. It doesn't do this all the time, but does it most of the time. This is why I'm pretty sure it has not been made DAO.
I have compared it to my M&P pre model 10. I can't tell what's going wrong!
Any ideas for a (hopefully) cheap repair?
Thanks,
dakasat

 

[dakasat]

Gents,
I have a Smith Model 10-5 that works well in DA. When it is cocked for SA fire and the trigger is pulled, the hammer engages the trigger in some fashion and the trigger kicks forward. It doesn't do this all the time, but does it most of the time. This is why I'm pretty sure it has not been made DAO.
I have compared it to my M&P pre model 10. I can't tell what's going wrong!
Any ideas for a (hopefully) cheap repair?
Thanks,
dakasat

 

[Randy Lee]

Greetings,

I can only guess as I cannot see the gun. But it sounds like the DA sear hitting the top of the trigger camming surface. If that is the case, then a new sear may need to be fitted to the gun. Not a terribly difficult operation, but it is best to be performed by someone familiar with the Smith revolver's lockwork.

 

[AzShooter]

[ Not a terribly difficult operation, but it is best to be performed by someone familiar with the Smith revolver's lockwork.

Randy do you know of anyone that could do that kind of work?

 

[Randy Lee]

Az, I wish I did. Then maybe I could get mine worked on...

 

[dakasat]

Thanks for the tip Randy! Looks like this one is gonna stay DAO. Too old and worn to sink too much into it. I'll try a little judicious tinkering.
Thanks again,
dakasat

 

[Alk8944]

Originally posted by dakasat:
Thanks for the tip Randy! Looks like this one is gonna stay DAO. Too old and worn to sink too much into it. I'll try a little judicious tinkering.
Thanks again,
dakasat

dakasat,

Don't "tinker" with it! S&W revolvers, any revolvers for that matter, are very sensitive to messing with them when you don't understand what is happening. There is a book available which will show you correctly how to repair your revolver, it is: "The S&W Revolver, a Shop Manual" by Jerry Kuhnhausen. It is about $25 from Midway, Brownell's, or just Google it and you will find many sources.

Now, the problem. What you are experiencing is a fairly advanced ""Push-off" condition. I won't go into the mechanics of why the trigger kicks forward, but try this. Cock the gun, then put moderate pressure on the back of the hammer spur without touching the trigger. No doubt you will find the hammer falls, hence, "push-off".

The cure is re-stoning the trigger sear to correct trigger pull. It is important to get it right the first time as the trigger is case-hardened only a few thousandths of an inch deep and it is easy to go through the case and into the soft core with only a few strokes of a stone. Whatever you do, do not try to stone the sear notch in the hammer. If the hammer shows wear and rounding of the notch it will require replacement.

 

[dakasat]

Alk8944,
Thanks for the info. Your point is taken as to not "tinkering" with this old revolver. I guess I should have phrased it differently. I plan to replace the sear and see if the problem continues. I may replace the trigger or hammer or just bob the hammer.
I may have to replace the mainspring with a Wolf spring.
In your opinion would this revolver work reliably as a DAO without working on this problem?
I'll pick the shop manual up asap. I've replaced springs on Smiths before, but I'm sorta lost on trouble shooting. I was hoping to go to the Smith Armorers class at Blackwater this month. Oh, well, I have you guys to help me!
Thanks again!
dakasat

 

[Randy Lee]

dakasat,

Was a trigger job performed on the gun previously? Push off can also occur if the rebound spring was cut- as is sometimes done by people wanting to lighten their trigger pulls( I do not recommend this). A rebound spring that is cut too short will not hold the trigger SA ledge in the hammer SA step with enough force and can allow pushoff to occur.

 

[dakasat]

I have no way of knowing if a botched trigger job has been done on the 10-5.
I spoke with Brownells Tech Support today. they told me to replace the hammer and possibly the trigger too. I just picked up an old M&P (pre model 10 (serial #308XXX) for $50.00. It's a parts gun. Looks like whats left of a parkerized finish. I tried the hammer and trigger from the M&P in the 10-5. Still doing the same thing!?!
Now, the 10-5 is not rotating every time I pull the trigger. Hmmm, what to do. My hair is too short to pull out!
I'm thinking if I can get the 10-5 to rotate reliably...bob the hammer on the 10-5 as was suggested by a fellow today....
Anyone got an idea how old the M&P is? Value...not functioning..?
Anyway, thanks for the help Gents!
dakasat

 

[Randy Lee]

Hi dakasat,

ok, to resolve the cylinder not rotating, I suspect that the torsion spring in the trigger is not applying pressure against the hand. The hand should spring forward if the torsion spring is seated correctly.

Please look at the rebound spring(trigger return spring). If it is a factory standard part, it should have both ends of the spring closed and ground flat. If someone cut a few too many coils off, that will cause the push off/stubbing and result in the symptoms you described. I cannot recall off hand what the overall length of the spring measures, but I shall get a reading when I get to my shop tomorrow and report back here.

 

[tomcatt51]

The stock rebound springs are right at 1.150" long. Just over 1 1/8".

When you swapped triggers did you leave the hand attached? Swap the trigger and hand as a unit? You want to keep the hand in the gun that was originally there. DON'T swap the hand/trigger as a unit. Swapping the hand can screw up your carry up. Assuming the hand spring is hooked up.

 

[dakasat]

tomcatt51,
I swapped the trigger witout the hand for a minute or two, tried the action and realized what I had done. I then replaced the correct hand to the correct trigger/ hammer.
How bad did I screw up?
Anybody know how old the old parts gun M&P that I referred to previously in this thread is?
I'm thinking about parting it out.
Thanks,
dakasat

 

[S&W revolverman]

The rebound spring, if original, should have 17 coils, and not clipped on either end as mentioned above.

Hope this helps
chris