GP100 help needed

Biggun Stump · Post by **Biggun Stump** » Wed Aug 19, 2009 6:14 pm

Took my GP100 apart today and polished the internals. Put it back together and the cylinder stop won't drop all the way in double action. Of course the cylinder won't turn and hammer only comes back about 3/8".

Single action works fine. Had it apart and back together again before without any problem.

Tell me oh GP100 Gurus, what have I done?

Post by **Bullseye** » Thu Aug 20, 2009 11:25 am

Welcome to Guntalk-Online!

It sounds like you may have installed the wrong plunger and spring combo for your GP-100's cylinder latch and that's causing a timing problem.

There are two similar plunger and spring sets in the GP-100. One is for the cylinder latch and the other is the hammer dog plunger. You want the longer spring & plunger on your cylinder latch. Is it possible that you might have installed the wrong plunger on the cylinder latch?

R,
Bullseye

Biggun Stump · Post by **Biggun Stump** » Thu Aug 20, 2009 11:58 am

Triple checked that to make sure. Springs are in the right places with plungers facing out.

Did some stoning on the back of the hammer dog and I'm wondering if I took off to much. Would this allow the SA to still work but not the DA?

What do you think?

Post by **Bullseye** » Thu Aug 20, 2009 12:17 pm

It's possible because the trigger has two separate surfaces: one for single action and the other for double action. You may have disrupted the timing for the double action by removing too much material off of the hammer dog.

R,
Bullseye

Biggun Stump · Post by **Biggun Stump** » Thu Aug 20, 2009 12:42 pm

Thanks Bullseye.

Since it's a restricted part, reckon I'll have to ship it off to Ruger.

sigh.

Appreciate your help.

Post by **Bullseye** » Fri Aug 21, 2009 4:14 am

I did some further research on your problem, the hammer dog shouldn't normally interfere with the timing of the cylinder latch. Its purpose is to cam the hammer rearward and maintain positive engagement with the DA cam portion of the trigger until the trigger extension is picked up by the DA sear. Did you polish (stone) any other parts inside your GP? Perhaps the cylinder latch (KH04504) or the trigger plunger (KH03200)? The DA late timing issue and DA cylinder binding you've described is typically caused by one of these two parts being out of specifications. If the nose of the stamped trigger plunger is too short it will cause the timing problem you've described. The little notch under the nose of the trigger plunger is the surface that pulls the cylinder latch down. Basically the cylinder is trying to rotate before it is being released by the latch causing the binding in DA mode. Another thing to check: could the trigger plunger (KH03200) have been installed upside down?

These are the things that I can think of to help solve the problem with your GP.

R,
Bullseye

Biggun Stump · Post by **Biggun Stump** » Fri Aug 21, 2009 10:14 am

On the cylinder latch: Smoothed the step the trigger plunger rides on.
On the trigger plunger: Buffed the nose on the underside which rests on the cylinder latch step.

Believe I'll try ordering two more of these parts before sending it to Ruger.
Worst I can do is have extra parts.

Thanks alot for taking the time to help me out with this, Bullseye!!!

You and this site are the best.

I'll let you know what happens.

Post by **Bullseye** » Fri Aug 21, 2009 10:37 am

Biggun Stump wrote:On the cylinder latch: Smoothed the step the trigger plunger rides on.

On the trigger plunger: Buffed the nose on the underside which rests on the cylinder latch step.

Believe I'll try ordering two more of these parts before sending it to Ruger.
Worst I can do is have extra parts.

Thanks alot for taking the time to help me out with this, Bullseye!!!

You and this site are the best.

I'll let you know what happens.

Perhaps the combination of smoothing both of those parts has left them enough out of spec to cause the delay in timing. Buffing shouldn't take off enough material to do this, but if you stoned either of these then that could do it. I would order both parts and replace the originals.

R,
Bullseye