I'm looking at a DIY kit from MCARBO, anyone have experience with them? Reliable after install?

I don't want to write out the whole procedure, as you can find it online. The kit you are looking at is reduced hammer and trigger return springs as well as hammer and trigger shims. I have not used that kit, but I have used the Wolff springs, as well as the trigger shim kits from Trigger Shims .com.

When it comes to the double action pull, you can get a huge improvement by working on the trigger return. I like to use the lowest power trigger return springs in the SP101 and GP100s, they function fine with them. The key is that you clean out the bore that the plunger ride in, most of them are rough, and often have burrs and other junk in them. That's one area Ruger should really improve on. The fix is to pull it apart (you find these instructions online), and use a drill bit that just fits in there with your BARE FINGERS to clean out any burrs inside. a gentle lapping with 400 grit sandpaper does not hurt. The plunger should free slide through the bore with no hiccups. If it does stick, fix it. Lube the plunger, and put it back together with the lightest return spring.

Polishing trigger surfaces can make some difference depending on how rough they are to begin with. I do it to any trigger I work on, but it doesn't seem to make a giant difference to mine. It's worth doing, you won't know how much you will gain unless you do it.

One overlooked thing is hammer dog shims. As they come the hammer dog is usually loose as a goose, and that means that dog is never contacting the trigger the same shot to shot. Shim it, it makes a difference.

The trigger shims I don't think make a monumental difference, but its not that hard to do, and it doesn't hurt.

The hammer shims do make a difference, this can often help a gritty feeling early in the trigger pull where the hammer can be riding on the frame. In theory it may even help you get away with a lighter hammer spring. It's too bad they are kind of a pain to put in, but I do it.

With the hammer spring, I have never got away with a 9 pound spring yet. They usually work single action, but double action they can fail with some primers. I'm pretty sure both my GP's have 10 pound springs in them. My SP101 I left the factory spring in, but using lighter should work.

Polishing the hammer spring strut is basically useless. I usually do it just because, but every one I worked on was fine the way it was.  A dab of grease on the strut doesn't hurt.



All that said, all of that is for the double action pull, and makes very minimal difference to the single action pull. It does make it lighter, but not by much, and it doesn't make it any smoother. The ONLY thing that makes any real difference to the single action pull is to polish the trigger, and you can find how to do that online. Sometimes doing the thumb trick can make a decent difference too.

Excellent info, this helps a lot, thank you! I may tackle the plunger hole tonight as there is definitely some resistance and grit upon reset.

I did the same as above, with a Wolfe kit.
The difference is astounding.
My SP101 has a great action now, and has never misfired.

I did this to mine and it made a huge difference.

Here's a really good video that shows how to do all that:

https://www.youtube.com/watch?v=txbCmzM4v6A&pp=ygUNc3AxMDEgdHJpZ2dlcg%3D%3D


I got my shims here:  https://www.triggershims.com/