GP100 action tuning

[444thumper]

I have a GP100 that I have smoothed up and am very pleased with it except for one point. I thought I would see if someone had already figured this one out as I am very happy to profit from someone else's experience. In double action mode, the first movement of the trigger is light and smooth, dropping the cylinder latch down. When it goes the next little bit and releases the latch back against the cylinder, however, there is a noticeable "bump" that the trigger has to go over. At first I thought it was the act of moving the cylinder but if I hold the cylinder just after it has started moving and move the trigger, it is clear that the resistance is in the latch linkage. It has the resistance even when the cylinder isn't moving, just the latch being released. The rest of the stroke is uniform. My question is this: What part is likely causing that "bump" in the trigger? What action do I need to take to smooth it out? Thanks in advance for any insight you can give.

John

 

[Chuck 100 yd]

At about that stage of the trigger pull the trigger goes from the hammers single action notch to the hammer dog,double action,stage and looses some leverage.
I like that staging because it tells me the trigger is about to brake. I seldome shoot double action ,but when I do, that slight difference in the trigger helps me to be more accurate.

 

[444thumper]

Thanks for the input. I have that on some of my Smiths and agree when it's close to the break. In this case, it's right near the start, maybe 1/4" of trigger movement and makes it hard to get a smooth pull started. I'll have to pull the trigger group and see if I can spot the movement at that point. Harder than Smiths where you can just watch it with the side plate off.

 

[Thel]

Found this on another board:

http://rugerforum.net/ruger-double-action/88762-22lr-sp101-trigger-job-question-multiple-threads.html

Go down to Exlogger's comments and pics. There are several other possibilities.
I would try to eliminate one by one. Perhaps there is interference between the pawl and the cylinder latch somehow. Another would be to look at the shape and contact surface of the hammer dog. I had one with a pit or void in it on one Ruger. Another would be to look at the trigger plunger. It also need surfaces that need polishing. An individual on another board also said that it could benefit from the use of shims as sold by Lance for Rugers.

 

[444thumper]

Thanks for the link, Thel. There 's some good info there. I also happened on some information by Kevin Wilson on a trigger job for the sp101, which has the same lockwork, even a video of the movement of the parts. May be of help to some of you if you haven't seen it.

http://www.sp101trigger.com/ and http://www.sp101trigger.com/trigger.html

Will give me plenty to work with when I have some downtime.

John

 

[Thel]

The K. Wilson trigger job outline is good. With all the mods and shims should be able to get double action to around 7 lbs. If you get FTF's also look at firing pin protrusion. It should be 0.055" and min. headspace of 0.060". Apex Tactical once stated he thought he could get the trigger down in the 5's for a game gun. There is a lot one can do to the guns.

On the Kevin Wilson writeup consider step 26 dealing with the trigger plunger. The top and top front sloped part that is to be polished is the area affecting the plunger return.