Ruger GP100 - light strikes

[Flexmoney]

I finally got around to getting some ammo (38spl) loaded and taking my used GP100 for a spin.

Out of about 30-42 rounds, I had 6 or 8 that had light strikes. I got maybe a couple of those to go off with a second strike, but the rest said no.

Federal primers, seated well below flush. I didn't double seat these, but I usually crush primers firmly into the pockets. I checked them all as I case gauged the rounds.

- I assumed this gun had stock springs in it, but I really don't know. I've got it apart, any way to tell, other than a trigger pull gauge?

- I'll have to get some feeler gauges on it to compare (unless there is a better way?), but the hammer on the transfer bar extends the firing pin much less than just pressing on the transfer bar. I understand this is an inertia driven system, so perhaps that isn't a huge factor. I've read where the face shelf of the hammer can be reduced a bit...to impact the frame later with the idea to transfer more energy to the transfer bar.

- The wear spot on the transfer bar looks a bit suspect. Maybe it is a bit short?

- The hammer does have drag marks on the sides.

- I'll check end shake (b/c gap and head space). I might as well shim that to optimum while I am at it. (Is there a specific shim kit for these? Hammer and trigger shims?)

- I have a Powers 1 jig (1911 adapter). I might as well get the GP100 adapter and slick the trigger while I am at it?

Feel free to chime in with any advice. Anything I should be sure to check? Anything I should be sure to modify ?

This is a 6in., full lug, in blue. I have the Hogue grip and the standard wood/rubber grip. Sights are stock.

I do have an Aimtech rail...and a red dot that might find a home there. Is that rail any good? It was free with the gun when I bought it. Look s like a copy of the Weigand mount...

I have a copy of Iowegan’s Book of Knowledge for the Ruger GP-100.

[Forrest Halley]

I don't know too much about Rugers, but the hammer having drag marks on the sides is no good. That's killing your inertia to the transfer bar system maybe no such a big deal on a stock gun. I have also relieved my hammer on Smiths so that the frame is not absorbing the hammer strike as much as the firing pin. Realize that with the transfer bar system you are eliminating the safety margin/feature little by little. Try power custom for shims for the Ruger. Best of luck.

[Carmoney]

Sounds to me like somebody installed a spring kit. But even then, I'm surprised it's not working with Federal primers seated below flush. It shouldn't take much to light those off.

Iowegan's information is as good as anything I've ever seen on the Ruger DA wheels. His real name is Gary and he used to post frequently on the S&W Forum--you might try contacting him directly by email if he's still around.

I don't think a jig is going to help you on the DA pull. I might be mistaken, but I believe the GP-100 jig adaptor is used to recut the single-action sear. And who cares about that, for the stuff we do anyway, right?

Proceed carefully, because I don't think Ruger will sell you replacement parts.

[Bill Nesbitt]

http://www.rugerforum.com/phpBB/

Search is your friend.

I found some good info on the Ruger Forum when I was trying to slick up an SP101 in 9mm. Iowegan has good info.

I don't know if it would be a good idea to have Ruger bring it back to stock before you start doing a trigger job or not.

[Tom E]

Proceed carefully, because I don't think Ruger will sell you replacement parts.

+1

Brownell's parts listing will give you a good idea what parts you can't buy. Makes you very carefull working on one. I've done the actions on a couple GP100's and they fired factory ammo no problem with a lighter mainspring. Wolff kit. I know there can be a FTF issue because of "too short" transfer bars on the Ruger single actions, I've welded and lengthened them, but I'm not sure if this is an issue with the DA's also.

Edited March 28, 2011 by Tom E

[Flexmoney]

http://www.rugerforum.com/phpBB/

Search is your friend.

I've had (and have) a few tabs on each computer open from a vast number of searches over the last few days.

I found some good info on the Ruger Forum when I was trying to slick up an SP101 in 9mm. Iowegan has good info.

I don't know if it would be a good idea to have Ruger bring it back to stock before you start doing a trigger job or not.

I'd hate to ship it off. I already am shipping out my brand new 642 (crooked barrel, ugly crown). What is it with these things?!?

[Bill Nesbitt]

Not too many people run Rugers for race guns. There might be a reason.

Even after I worked on the action on my SP101, the trigger is so long and funky that it just sits in the safe.

After I have shot S&W's that have been touched by the likes of Carmoney and Randy Lee, then nothing else is good enough.

[cas]

- I'll have to get some feeler gauges on it to compare (unless there is a better way?), but the hammer on the transfer bar extends the firing pin much less than just pressing on the transfer bar. I understand this is an inertia driven system, so perhaps that isn't a huge factor. I've read where the face shelf of the hammer can be reduced a bit...to impact the frame later with the idea to transfer more energy to the transfer bar.

Usually when there's a problem with them that's it. They have insufficient transfer bar clearance on the hammer face. The transfer bar ends up taking the full force of the hammer, it gets battered and breaks. Ideally they should share the load, the hammer nose bottoming out the same time the transfer bar does. You could have too much space though. What's the firing pin protrusion into the frame window look like?

Edited March 29, 2011 by cas

[MartinLei]

I had light strike on my GP-100 a while ago. I had trigger job done and light springs on it, but it didn't give me any problem for the first couple of hundred rounds. After that it was constant trouble. Initially I blamed the WWB ammo, but later my gunsmith found the hammer dragging on the frame a little. He installed shims on both sides of the hammer to keep it away from the frame and problem solved.

[Flexmoney]

I checked the end shake and B/C gap. Both were on the high side, but not really out of spec.

For head space, you are suppose to use virgin brass to check. Like I have a supply of virgin anything.

Head space looks good to my Mk1 eyeball.

Seems like hammer and/or springs.

I cleaned the gun up and put her back together. I am going to run out to the local indoor range to verify the malfunction. I'll also put some of this ammo through my J-frame to make sure that isn't suspect (especially with the recent thread on Federal primers).

Thanks for the input so far!

[Tom E]

Hold the trigger back at the point of the hammer falling (DA) and see how the end of the transfer bar sits relative to the firing pin.

[Flexmoney]

Hold the trigger back at the point of the hammer falling (DA) and see how the end of the transfer bar sits relative to the firing pin.

I gave that a good look, but I have nothing to compare it with. (Maybe I'll get back to searching for pics or measurements.)

From the wear marks, I suspect it.

I got some rounds through it this weekend. The ammo is fine...shoot well through the J-frame.

[ben b.]

Hold the trigger back at the point of the hammer falling (DA) and see how the end of the transfer bar sits relative to the firing pin.

How should it sit?

[JerryShoots]

Flex,

I've got a lot of shop time on GP-100's and they all tend to light strike with reduced hammer springs. Your best two options are...

-Go up in spring poundage to at least 10# this seems to be the magic minimum for the Ruger.

-An extended firing pin which works great but is more expensive.

As I recall you live close enough to me for this to be cheap. PM me a mailing address. I have a couple sets of the Wilson and Brownell springs. I'll drop one in the mailbox to you tomorrow. See if that helps before going further. If it does keep the spring.

Also the GP-100 strut that the spring rides on is a tad tricky to take apart. That pin that locks it most come out for the change and getting it back together is a real pill. Make sure you throw on some glasses or we may start calling you one eyed flex

[Tom E]

Hold the trigger back at the point of the hammer falling (DA) and see how the end of the transfer bar sits relative to the firing pin.

How should it sit?

The trigger raises the transfer bar and sometimes tolerances are stacked so it doesn't get raised far enough and the transfer bar isn't up over the firng pin to fully transmit the hammer strike. You also look at the firing pin side of the transfer bar to see the contact pattern. Then there are transfer bar thickness issues (acts like a too short firing pin) which are cured by grinding the hammer or thickening the transfer bar.