M*CARBO Brotherhood

LC9s Three trigger mods installed

I’ve seen three different trigger mods for the Ruger LC9s that people have installed but I haven’t seen any information from people who have installed more than one mod. I decided to install all three mods to see if they were compatible with each other. The mods are:

MCARBO trigger spring kit, which replaces the striker spring, striker block spring and the trigger return spring.

PRP trigger kit, which replaces the sear and trigger pivot with a modified sear and trigger pivot.

Aegis short stroke trigger, which replaces the trigger with a modified trigger. The Aegis trigger is not compatible with the magazine safety, which must be removed when the trigger is installed.

I installed all three mods at the same time, so I can’t tell how much of an effect each mod had individually. Total installation time was about an hour.

I ran into two problems. The modified sear in the PRP kit prevented the safety from working. I contacted PRP support and they immediately sent out a replacement which worked fine. I was very pleased with PRP’s support.

The second problem I had was that after all three mods were installed, the trigger wouldn’t fire on every pull. More accurately, you couldn’t pull the trigger back far enough to fire. The trigger safety was keeping it from firing. I ended up reinstalling the original return spring and everything worked perfectly.

Unfortunately, I don’t have access to a scale to measure the pull weight, so I took it to a local gunsmith to have it measured. The gunsmith was a real old-timer (I’m 66) and he had an old mechanical scale. Prior to the mods being installed, he measured “about 4 and a half” pounds. After the mods were installed, he measured “about 4” pounds.

I’m not an expert, but I question his measurements. To me, the trigger pull feels significantly less than it did pre-mod. I wish I had access to a good, digital scale to get an accurate measurement.

What I was able to measure was the trigger pull length and trigger reset length. Pre-mod, there was 3/8" dead length before you felt any resistance. From the point of first resistance to the firing point was 5/16". From the firing point back to the reset point was 7/16". Total trigger travel was 11/16", or just short of 3/4"

Post-mod the dead length is only 1/8". From the point of first resistance to the firing point is only 3/16". From the firing point back to the reset point is only 3/16". Total trigger travel is 5/16", or just over 1/4" or not quite 1/2" less than the pre-mod travel!

As you can see, the trigger travel is significantly less after the mods were installed as is the pull weight. I also think the replacement trigger has a much better feel and is much more attractive. (I opted for the red anodized trigger.) According to the manufacturer, it also eliminates the “trigger bite” that some people have experienced.

Hopefully, this information will be helpful to anyone considering installing one or more of these options.


My LC9S has thousands of rounds through it (unsure exactly how many as I bought it used) but I lately have experienced multiple failures to eject with varying ammo. Ruger sent a replacement recoil spring at my request for no charge, but I am wondering if the extractor or some other component may be worn and causing the problem. Any thoughts or suggestions?


Sorry to hear about your problem. I wish I could help, but I’m just learning about guns myself. The reason I was able to install the trigger mods was because of the excellent video instructions each company has on YouTube.

If you can’t turn up any info on the Internet, you might want to get Ruger involved. I haven’t had to deal with them yet, but my understanding is that their aftermarket support is excellent.

Good luck and let us know if you find a solution.

1 Like

That’s where I’d look first. The extractor and spring total about $10.50 plus shipping so it won’t break the bank to just go ahead and replace them.


Thanks. Is this the correct spring and are the parts identical in the LC9 and LC9S? I hope I can find an installation video.

1 Like

This much I do know. The LC9 and LC9s are different guns. The LC9 is a trigger fire and the LC9s is a striker fire. Mechanically, they are completely different.

1 Like

I don’t know. This is the parts list I found on Ruger’s site when I selected LC9S. I’d email customer support and ask them.

1 Like

Thanks all. I emailed Ruger support. I do realize the substantial differences in the firearms which is why I posed the question.

I spoke with Ruger today asking whether I should try replacing the extractor and ejector. That followed my email to them asking for advice and the proper part numbers to which they promptly responded giving me a number to call.
Instead of giving me part numbers so I could order what I need, they are sending me a replacement extractor and ejector for nothing. That is the same thing they did when I asked about replacing the recoil spring.
There almost surely are better firearms out there but I am extremely impressed with Ruger’s customer service.


I commented above about the high quality of Ruger Customer Service:

I yesterday received and installed the new extractor and ejector (Ruger also included a new extractor spring and lock). I went to the range today and in firing 50 rounds had absolutely no problems - no failures to eject, no nothing. Remember that I bought this firearm used and the wear indicated that it had fired many rounds. I have since put several thousand through it. For Ruger to send me FREE replacement parts is nearly inconceivable.

That said, I do not ever again want to replace the extractor in an LC9s. It was a royal PITA. While I had the firearm broken down, I somehow managed to lose the spring to the magazine safety and therefore ended up removing it. I will not shed any tears over that although I twice lost the spring to the trigger safety as the trigger had to be removed to get the magazine safety out.


Did that on a Ruger SR22. I tore it down to polish everything and getting it back together was a ‘challenge’. The disconnector and spring kept falling out but I was too happy I got the side plate on to want to take it apart again for that useless piece of plastic. Good riddance to it.

As to Ruger’s excellent customer service, I emailed them when I couldn’t find a replacement PC9 buffer retainer on their web site to buy. They sent me one right away and didn’t charge me for it. If I still had any firearms, many of them would be Rugers.

1 Like

I can tell you that my LC9s had a trigger pull of 6lbs even more or less - it varied by an ounce or two, depending on where on the trigger I “pulled” it with my cheap mechanical scale. After I installed the MCarbo spring kit, and polished all the internals with Flitz and a Dremel, it pulled at a consistent 3lbs, so I call bullshit on your gunsmith’s measurements. I have also done the same work on 3 other LC9s and EC9s pistols. They all started in the high 5lb or low 6lb range, and they all dropped their pulls by about half after the kit and polishing.

I want to update my original post. I indicated that I was unable to use the trigger spring from the M-CARBO spring kit because it was causing problems with the trigger safety interlock. I have since filed down the top of the trigger safety interlock so that the pistol now fires consistently and the trigger safety interlock still works as it should. As of now, all three modifications are installed and working as they should. The trigger pressure is feather light. Unfortunately, I have no way measure it.

If anyone is thinking about installing any or all of the three modifications that I installed, I would definitely recommend any or all of them!

1 Like

Welcome back @droid714
Glad you got it worked out. Stick around this time!