Problem with SP101 action

[Monster Zero]

Doing a second action/trigger job on an SP101 according to the MCARBO video that's available. The first SP101 went well, considering it was one's first try at it. Had to buy a new pawl spring but hey, no big deal.

This time, when finishing up the reassembly and installing the new mainspring assembly, the action will work in single action just fine. However, trying to get it to cycle in double action, the trigger doesn't reset with whatever it's supposed to inside there and it just moves back and forth but doesn't do anything.

I suppose one could just tear the whole thing down and start over... not really looking forward to messing with that pawl spring again though. Anyone have any suggestions about what might be the problem that one could check for an easy fix? So far I've taken the whole thing apart, refitting the hammer shims and then put it back together a couple dozen times or so.

Help!

TIA

 

[JohnKSa]

Possible causes:

Hammer dog is missing/got left out on reassembly.
Hammer dog was re-installed incorrectly to the hammer.
Hammer dog spring and plunger were lost/left out.

 

[Monster Zero]

Possible causes:

Hammer dog is missing/got left out on reassembly.
Hammer dog was re-installed incorrectly to the hammer.
Hammer dog spring and plunger were lost/left out.

Thank you. I'm pretty sure I got all those things right, but I'll pull the hammer and check them again later this afternoon.

 

[JohnKSa]

If all those things are right, that would be pretty bad. If the DA trigger can move all the way forward and all the way back without any effect and everything about the hammer dog installation is correct (installed correctly with spring and plunger) then it sounds like it could be that too much metal was taken off the hammer dog nose or off the curved convex surface at the top of the trigger where it engages the hammer dog nose.

 

[Riomouse911]

Ruger SP101 Trigger Job Guide

This is a great step by step. I believe the second set of steps covers the hammer dog work among others.

Stay safe.

 

[P89DCSS]

If the SP101 was functioning correctly before op worked on it then odds are very high he made a mistake. It's not a simple task to line up everything with two hands. I use a mechanics bench vice with polyurethane jaws to hold it securely. Frees up both hands to get it right. Magnifying 4x readers and an led headlight really help too.

 

[Monster Zero]

Thanks to all.

Turns out that yes, the hammer dog was the problem. It was facing correctly, and the spring was in place. However, I had tightened it up just a bit too much with two shims. I took out one of them and everything is fine.

 

[JohnKSa]

Very good! That's a pretty simple fix.

 

[Riomouse911]

Glad you solved it!

Now let us know how it shoots for you when you get a chance .

Stay safe.

 

[Monster Zero]

Glad you solved it!

Now let us know how it shoots for you when you get a chance .

Stay safe.

Range report. First and most importantly, Mrs. MZ, upon hearing the news and seeing it presented to her with the cylinder open, sez, "Can I dry fire it"? ClickClickClickClickClick....

OH YEAH, I LIKE THAT!

So last night we're off to a good start. Today, I took it to the indoor range, and like any other quality handgun it shoots better than I do. It's a much more joyous experience now, though. Out of 60 rounds, there was one FTF but I'm ascribing that to just one bad round, for now. It was factory ammo. If it happens again I'll swap out the 9# spring for the 10#. Somehow I accumulated a handful of mainsprings, all between 9# and 12#. I'll probably throw the 12#'s in the trash...

This one's the 3" model, BTW. It shoots the old Winchester 110gr .357 load, which is an old favorite, like a boss and with the Pachmayr compac grips the recoil is... uh, pleasant, actually, but it does go BOOM.

Thanks again to all for the help with it.

 

[JohnKSa]

Sounds like the spring is a bit light--misfires should be really rare with decent factory centerfire ammo. In a self-defense gun, I'd be pretty unhappy getting a misfire in the first range session after dropping the spring weight and would immediately go to a stronger spring without waiting to see if it was going to happen again.

By the way, just as an aside, testing for sufficient hammer strike energy should be done 100% DA. The SA hammer strike is a bit more energetic so testing in SA isn't really a good representation of how the gun will perform DA.

 

[WrongHanded]

I have experienced reduced weight hammer springs that were 100% reliable after installation, then be far less reliable a couple months later after the spring took a set.

I would settle for smooth rather than go as light as the gun will function.

 

[Old_Grouch]

I would settle for smooth rather than go as light as the gun will function.

Absolutely! If you want an easier trigger pull I think it's better to strengthen your hand than to weaken the gun.