M*CARBO Brotherhood

GP100 Trigger Problem After Trigger Job


New guy here.
I recently picked up a Ruger GP100 4 inch blue 357 Mag. I also picked up up the necessary things to do a trigger job on it from Mcarbo. The YouTube video was great. I followed it. I did the disassembly, polishing, and reassembly with the new Mcarbo springs. It all went well until I installed the trigger group back into the frame. Now the trigger does not have full range of motion. I can’t move the trigger back far enough to get the hammer in the frame correctly. The trigger mechanism is hanging up somewhere. I removed the trigger group from the frame and took it all apart and checked everything and it looked OK. I put it back to gather and tested it to see if was hanging up outside of the frame by itself. It wasn’t. I have had it in and out of the frame about 6 times. Still no go. It appears the pawl is working correctly as it advances the cylinder, but right after that you can’t pull the trigger anymore. Any ideas would be helpful. Thanks!


check the positioning of your trigger return spring. the newer models use a lighter spring than the older models, and there has been some issues logged with ruger with trigger return…


Thanks for the reply!
I was thinking that might be the issue. I have taken the whole trigger return spring and plunger out twice and checked it and couldn’t find anything wrong. Like I said earlier the trigger seems to work like it should when the trigger group is out of the frame. When I install it back in the frame I can only pull it back about half way before it won’t move anymore. It’s got to be something simple that I’m doing wrong for sure.


@smbob Read this on the Ruger Forum. You may have switched the paw spring and detent with the cylinder lock detent and spring. Switch them and see if it fixes the issue. The cylinder lock detent and spring are the longer of the two. Also 18 or 22mm trigger springs have been used on the GP100 depending on when it was made.


pretty good - even for the SP101 series

(if anyone has an extra copy of the SP101 IBOK i am definitely interested)

hope you get your trigger group sorted out - it’s not really that complicated - DO NOT PULL THE TRIGGER WHILE THE TRIGGER GROUP IS OUT OF THE FRAME!


on the Gulf of Mexico


Thanks for your reply!
I never removed the cylinder lock detent, so I can rule that out. I will try and switch to the factory return spring and see if that helps.


is the firearm new/un broken In? if so, put the factory spring back in place, till you run at min 500rnds thru it, let it wear in then shift the spring…



Good point, Buck! We all forget what is ‘suggested’ during a manufacturers BREAK IN period??? With vehicles, it is 500 miles, guns 500 rounds! There is this ‘process’ that happens with friction and metals that is so difficult for us ‘common folk’ to figure out? Some sort of ‘scientific phenomenom’ that occurs… Then ‘we’ end up being that BAD GUY that doesn’t follow the manufacturer’s recommendations! :thinking::crazy_face::+1: :+1:NOW, HOW CAN THAT WARNING LABEL/PICTURE BE SHOWN IN AN OWNER’S MANUAL THAT WILL (NEVER) BE VIEWED BY MOST NEW OWNERS!!! MY CYNICAL FACE LOOKING OUT TOWARDS THE GENERAL PUBLIC… ( I KNOW THAT I AM ONE TO BLAME FOR THIS AT TIMES…) Is it due to ‘laziness’ or the anticipation of ‘playing with a new toy after waiting what seems to be an eternity’ because of our excitement??? :+1:


I didn’t just wildly pull the trigger with the trigger with trigger group out of the frame without regard for the pawl spring plunger, trust me. I have been working on firearms for over 40 years and I have been a Machinist for over 40 years as well. I’m no rookie. I know how things work. Unfortunately I have an issue with something going on here. Hopefully with everyone’s help here, we can get it resolved.
I really appreciate everyone’s help! You guys rock!


welcome to the forum enjoy your stay have fun and gain knowledge


gotcha! that pawl spring plunger is fun to replace! almost as much fun as replacing the latch plunger in a Charter revolver (although a simple tool made out of a folded piece of stainless ruler makes the task a snap)

keep us up on how your GP100 runs!

on the Gulf of Mexico


Will do Willie. Thanks!


Thanks Goblin. I will give that a try.
I appreciate everyone’s input!


Show me that in any manufactures website or manual. I would really like to see the basis of your assertion.



That was speaking figuritively, John. Cars DO have a ‘break in period’ of changing the oil after the 1st 500 miles! I wouldn’t expect one to shoot 20-30 rounds through a gun and decide to do a trigger job on a new gun without getting a ‘feel’ for.the firearm (using 500 rounds, as a guide.) I did however compliment Buck on suggesting to 1st switch back to the factory spring. You are correct that I should have taken more time to expand on my thoughts. There are many DIY people in our group who enjoy working on their firearms and are ‘learning’ the ropes through their purchases with M*CARBO products. Should one be so cynical to believe that any one of our brothers are incapable of a ‘successful’ installation? If you notice that most aftermarket companies have disclaimers on their packaging and invoices as to avoid a lawsuit and perform the upgrades at ‘your own risk.’ I am glad that there are knowledgeable people to make suggestions when one of our brothers/sisters gets stumped when doing a job. However, if there is any questionable risks and one does not feel comfortable, he or she should STOP and seek out a gunsmith. I do not claim to have any mad gunsmithing skills. If something works for me, I am happy to share. When I fail, it is also important to share, wouldn’t you think? I am humbled from all that take their time posting their experiences here.


@Johnksg Was looking to purchase a RIA 1911 and checked out their warranty. They say 500 rounds recommended. Also my JD Gator, had to change oil and filter after the first 8 hours. Damned paint ain’t even burnt off of the exhaust yet. What a crock of $hit!!!:-1::-1::-1:


Thanks for everyone’s help! I switched back to the factory trigger return spring and BAM! It works like it’s supposed to. With the polishing, the shims, and the new hammer spring the trigger is very much improved! Thanks MCARBO and everyone here on the forum for your help. Much appreciated!


@Don68 @lonewolf was not talking about cars, but the assertion that guns need a 500 round break in period. (Usually you hear something like that from a 1911 owner.) :grin:

The Armscor manuals do say that…but what does that mean? What actions must the shooter take if any? (How does it affect their warantee?)

All it means is that for the first 500 rounds your parts will be a bit tight and your springs stiff as with any pistol. There is none of this shoot one clean, shoot two clean, nonsense!

PRS shooters do this with precision rifles for about 25 rounds. (They also change barrels at the 500 round mark - anyone plan on doing that?)

Now I am NOT calling out an individual, just a persistent myth and misunderstanding that just will not die. (Like loaded magazines). :astonished:



You are correct! This was NEVER a ‘calling out’ matter! The firearm manuals are vague in their warranty efforts! In my personal belief system many manufacturers did not figure on the scale of which the industry was going to become. I mean that there is a ‘sport’ of hunting and of course personal protection… Now, awaken the world of ‘competitional’ shooting! The ‘verbage’ in the manuals NEVER have evolved to date as it should! A lot of effort to write a bunch of jargon on safety to protect theirselves from lawsuits and of course consumer awareness was a major concern! Other than the fact that the industry never had any assumption on the growth of the DIY crowd! Springed parts and pourus metals can be ‘unpredictable’ until broken in and there are many factors that affect a firearm. Ultimately, all shooters are different and expectations vary? There are so many choices of ammunition, temperature issues and so many ‘variables’ to affect everything? Can there be a concise answer to your original question… My intellectual thought tells me that you may not be ‘satisfied’ to a certain degree. You seem to pick things apart and anylize theories and are purely a ‘result’ driven individual…:+1: I do admire that! With that being said, EASE UP SOLDIER… It is ‘great’ to challenge one’s mind at times, but DANGER WILL ROBINSON. BRAIN IN OVERLOAD MODE!!! :grinning: I wish that I could give you a more concise answer…


It was not my question…you made the statement.

Let me now ask you a simple question, and try to give a straightforward answer if you can.

What actions do you perform for your “break in period” that you claimed was necessary for a pistol?

Its a simple question…just list the steps for me since I do not know.