Ruger Firing pin

[Makicjf]

I'm fiddling with a old half lug 6 inch GP 100.  I've got it smooth, but with the lighter springs I'm getting 1-8 light hits.  A single action drop ignites the primer.  I've eliminated the hammer rub on the frame, polished the sides, and after todays lunch time attempt, reduced the hammer nose to get harder impact on the transfer bar.  I have not fired it since the nose job.  I did, however, upon reassembly in the parking lot of the vet school, note that the firing pin, with the trigger buried does not have much protrusion.  Are there old GP 100 extended pins available?

    Also, does the impact from the transfer bar drive the pin past the visible pin with the trigger buried:  am I seeing a partially rebounded position of the FP before the trigger reset?

After this weekends South regional where I'm shooting Open ( I've been shooting a dot for OSR Steel Challenge.  All of my shooting for 2 months USPSA and Steel Challenge has been with a dot.  I  finished my goal to close the the South Regional to dial up on L6 irons) I intend to start prepping for L6 at the IRC.  I'd love to shoot this Ruger.

Jason

[Farmer]

31 minutes ago, Makicjf said:

I'm fiddling with a old half lug 6 inch GP 100.  I've got it smooth, but with the lighter springs I'm getting 1-8 light hits.  A single action drop ignites the primer.  I've eliminated the hammer rub on the frame, polished the sides, and after todays lunch time attempt, reduced the hammer nose to get harder impact on the transfer bar.  I have not fired it since the nose job.  I did, however, upon reassembly in the parking lot of the vet school, note that the firing pin, with the trigger buried does not have much protrusion.  Are there old GP 100 extended pins available?

    Also, does the impact from the transfer bar drive the pin past the visible pin with the trigger buried:  am I seeing a partially rebounded position of the FP before the trigger reset?

After this weekends South regional where I'm shooting Open ( I've been shooting a dot for OSR Steel Challenge.  All of my shooting for 2 months USPSA and Steel Challenge has been with a dot.  I  finished my goal to close the the South Regional to dial up on L6 irons) I intend to start prepping for L6 at the IRC.  I'd love to shoot this Ruger.

Jason

I believe they relied on inertia to push the pin out farther. My old Security Six is that way, with the hammer cocked you can push on the transfer bar and get X amount of protrusion. If you push on the firing pin you can get a bit more. 

[Fishbreath]

How light on the mainspring? Wolff 10lb is as light as I've reliably gone on any of my GP100s. (Or, measured just under the hammer step, a hammer fall of about 1.75lb-2lb on GP100-size guns, depending on where in the tolerance band the spring is.)

 

If you haven't yet, get a pack of shims (I like Lance Shively's, at TriggerShims.com, because they have a bit more outside diameter and therefore more anti-tilt properties) and shim until the hammer fall weight goes up, but no further. I turn in the noses of my hammers a bit, filing a 10-20° angle in, so that the hammer falls further without any possibility of interference. Not sure if that's a cargo cult modification or a functional one, however.

 

Bowen makes an extended pin for both GP100 bushing styles. I don't know if it made a very big difference for me, though. I've had some luck with a reduced-power firing pin return spring in my guns, but I'm pretty sure the spring is different between the old and new bushings. If you do go the extended route, I'm pretty sure tip shape makes a significant difference, and some fitting is necessary. Note that a reduced hammer step appears to lead to faster firing pin spring wear, in my experience.

 

The firing pin will extend a little beyond its rest position with the trigger pulled. if you take the trigger assembly out of the gun and push the firing pin in with a punch, that's the full extension. (At least with the new-style guns, and Iowegan's Book of Knowledge, which was written before the new bushing, says the same.) Spec for protrusion is 0.055-0.065. I think you can also angle a punch in behind the transfer bar to push the pin in without taking the gun apart.

 

I have some anecdotal evidence that a lightened transfer bar can make a difference, too, although that's on my Super-size guns. I think there's a factory lightened option for the big guns, at least based on part numbers I've seen and what's come with my 9mm guns, but the principle may still hold for standard GP100-size transfer bars.

 

I also put everything I think I know about GP100s into a video, which may be of use.

[Makicjf]

10 minutes ago, Fishbreath said:

How light on the mainspring? Wolff 10lb is as light as I've reliably gone on any of my GP100s. (Or, measured just under the hammer step, a hammer fall of about 1.75lb-2lb on GP100-size guns, depending on where in the tolerance band the spring is.)

 

If you haven't yet, get a pack of shims (I like Lance Shively's, at TriggerShims.com, because they have a bit more outside diameter and therefore more anti-tilt properties) and shim until the hammer fall weight goes up, but no further. I turn in the noses of my hammers a bit, filing a 10-20° angle in, so that the hammer falls further without any possibility of interference. Not sure if that's a cargo cult modification or a functional one, however.

 

Bowen makes an extended pin for both GP100 bushing styles. I don't know if it made a very big difference for me, though. I've had some luck with a reduced-power firing pin return spring in my guns, but I'm pretty sure the spring is different between the old and new bushings. If you do go the extended route, I'm pretty sure tip shape makes a significant difference, and some fitting is necessary. Note that a reduced hammer step appears to lead to faster firing pin spring wear, in my experience.

 

The firing pin will extend a little beyond its rest position with the trigger pulled. if you take the trigger assembly out of the gun and push the firing pin in with a punch, that's the full extension. (At least with the new-style guns, and Iowegan's Book of Knowledge, which was written before the new bushing, says the same.) Spec for protrusion is 0.055-0.065. I think you can also angle a punch in behind the transfer bar to push the pin in without taking the gun apart.

 

I have some anecdotal evidence that a lightened transfer bar can make a difference, too, although that's on my Super-size guns. I think there's a factory lightened option for the big guns, at least based on part numbers I've seen and what's come with my 9mm guns, but the principle may still hold for standard GP100-size transfer bars.

 

I also put everything I think I know about GP100s into a video, which may be of use.

I don't remember which weight I have installed. It may well be the lightest spring in the three pack.

The balance between the return spring  installed and the middle weight spring felt off, the return felt sluggish.  

I'll check the protrusion tonight.  If it's in spec, I'll leave it alone.

I may well end up putting the heavier mainspring back in.

I'll check on some primer only cases this evening.

Thanks!

Jason

[Fishbreath]

The lightest one in the Wolff kit is a 9lb, IIRC, and those have always been a little iffy for me. (I'd love to get one working 100%, though.)

 

One in eight light strikes is probably a bit too much for this trick, but if you're closer to 1:100, you can use an M5 washer on the hammer strut between the spring and the spring seat to add a bit of preload, and thus a bit more ignition energy out of a given spring.

[Makicjf]

1 hour ago, Fishbreath said:

The lightest one in the Wolff kit is a 9lb, IIRC, and those have always been a little iffy for me. (I'd love to get one working 100%, though.)

 

One in eight light strikes is probably a bit too much for this trick, but if you're closer to 1:100, you can use an M5 washer on the hammer strut between the spring and the spring seat to add a bit of preload, and thus a bit more ignition energy out of a given spring.

I went back to the mid weight spring, changing the hammer step made no real change.

If I'm going to shoot 38 for the rest of the year,I'll need to accept what I have ( or pick up a 686).

The trigger is light enough, but I can feel the start of the spring compression, the cylinder stop engaging the reset...

It's a very different feel than all my smith's.

It's not bad, just longer more mechanical.

 

I bet at speed(or as "speedy" as I get), if I hit the reset, I'll never notice the differences

Thanks for your help.

Jason

 

Edited June 5, 2023 by Makicjf

[Fishbreath]

1 hour ago, Makicjf said:

The trigger is light enough, but I can feel the start of the spring compression, the cylinder stop engaging the reset...

 

There's a tiny bit of takeup in all three of my guns before the DA hook on the trigger picks up the hammer dog, but you may be able to smooth out the rest of the pull by working on parts of the mainspring strut. Try a bit of oil on the round tip of the strut. If that helps, a tiny dab of Flitz and a thousand or so dry fire pulls will make it more permanent. If not, try generous oil on the interface between the strut and the strut seat. If that helps, smoothing and polishing the strut at that point will help.

 

To reduce the cylinder latch click, you can smooth and slightly round the underside of the arrowhead-shaped nose of the trigger plunger (the part that moves back and forth around the trigger pin, under spring tension from the pawl plunger spring) if you have a lot of room to spare in cylinder latch timing (i.e., if it's not hitting the cylinder right next to the previous notch). I don't bother, though—even shooting DA groups, I don't notice it.

 

Numrich sells new trigger plungers, so it's not the end of the world if you go too far. There's a section on fitting them in my video.

 

All that said, my 6-round gun is a little less smooth than my 8-round guns, and I haven't figured out exactly why yet.

Edited June 6, 2023 by Fishbreath

[Makicjf]

10 hours ago, Fishbreath said:

Try a bit of oil on the round tip of the strut. If that helps, a tiny dab of Fli

That made a huge difference in the take up!

I'll do some more polishing !

Jason