Spring kit for Mossberg MC2C failed

Hi folks,

I bought a new Mossberg MC2C and installed the Spring Kit for it.

While the video was excellent and very well done so that the exchange of three springs was super easy, one of them failed, and failed big time. It was the firing pin / striker spring - the biggest and heaviest one.

After installing the kit and reassembling the pistol with a full function check including trigger reset, I noticed that the trigger was not returning all the way forward unless I pushed or pulled on it the last little bit, (which it did not do before exchanging any of the springs), and that the trigger safety was catching on the recess in the frame; which it did not do before exchanging any of the springs.

I replayed the video several times to see the close up view of the exact position of the firing pin assembly parts and everything lined up exactly as shown with the slide off of course, including the slight distance of perhaps 1/16" that one part could go further forward fully in its recess.

I disassembled the firing assembly and trigger bar again as per the video and reassembled it with everything in its proper place - just as before, but when I pushed it all down into the frame, I pulled on the trigger and trigger safety with a steady pressure to keep it all as far forward as I could, and reassembled the gun. I did my full function check with reset and it worked great. YAY !! It was fixed. (or so I thought) Then I removed the slide again and oiled everything that needed oiling nice and smooth.

The next day (today), I took it out of its box to try it again. The problem had returned just as badly with every trigger pull or testing every reset. @#$% it !! As i thought about it for a few minutes, I realized that it may very likely be the fault of the new MCARBO firing pin / striker pin spring as it is not only lighter, but a good amount shorter, and perhaps its too short and/or too weak, or both, to push the trigger and trigger safety fully forward as it needs to like the factory spring did 100% reliably.

So I tested my theory and removed the MCARBO spring and reinstalled the factory spring, reassembled the slide, fully function checked the pistol, and VIOLA !! It was fixed and as good as new again. YAY for Tom !! Now I actually have total trust and confidence in my new pistol as I should.

So the moral of the story is that, for at least my specific MC2C, and the specific firing pin / striker pin that I got and installed; it failed big time to function as intended and as reliably as it should.

MCARBO … it’s time to go back to the drawing board and test other springs that are long enough and powerful enough to prevent this so much as one more time for anyone. Period. I’ve used a few of your spring kits for my CZ P09’s and my CZ P-07, and had a similar issue that I was able to resolve by (again) reinstalling the factory trigger return spring in each one.

I would strongly suggest using a spring of the same length but perhaps not as heavy and test the heck out of it, and then replace ALL of your MC2C kits with THAT new firing pin / striker pin spring.

Irritated, but not fed up, and realizing that every gun is different just as every spring is different due to tolerances, material strengths, etc. - now I’m happy with it as the sear spring and the firing pin blocker spring did help to lighten and smooth the trigger pull as I don’t care nearly as much about the weight of the pull as I care about its reliability every single time.

MCARBO: this one needs immediate re-evaluation and testing.




Hey Tom, have you tried reaching out to their customer support or tech team? I know I had this same exact issue before polishing or breaking in. After polishing, worked great! But I would recommend calling them and at least letting them know you’re experience so they can address it.


I didn’t have the trigger reset problem. I did however have light primer strikes (8 or of 100 rounds). I replaced the factory striker spring and ran another 100 rounds. No issues with light primer strikes. I think a rework of the kit is probably in order.


Having recently purchased an MC2C and currently awaiting delivery of the M*CARBO Mossberg spring kit this thread doesn’t inspire confidence that this kit upgrade is going to work. Of the three springs that come with the kit the striker/firing pin spring would be the one I’d install and test first because the factory spring is way heavy esp. at the “creep” just before the break. It really stacks heavy. Shooting from trigger reset is no better. The trigger isn’t horrible it’s just not particularly great.

With the information gleaned from the OP and other thread respondents I will likely just change out the striker/firing pin spring and try it first to see if I get any light strikes or other reset issues.

We shall see.


It just occurred to me that the problem with trigger reset may not be caused solely by the lighter striker/firing pin spring. It might also be caused by the lighter “sear” (trigger) spring. Some Glock spring upgrade kits include a trigger spring that’s actually heavier than the OEM one to facilitate a faster trigger reset.

I dunno…something to think about.

My Mossberg spring upgrade kit arrives today. Will probably do the thing and take it to the range tomorrow.


The spring kit arrived this afternoon and I had it completely installed in less than 30 minutes which included watching the video tutorial one more time for good measure.

The trigger pull is noticeably smoother and lightened with all three new springs installed but it feels almost too light. Installing the striker (firing pin) spring was almost too easy. I decided to remove the MCARBO striker spring and put the OEM spring back in. With 2 of the 3 springs replaced the trigger feels pretty good. Not quite as light/crisp as I’d like but better than stock and I don’t detect as much “stacking” during the creep before the trigger break. I’m going to stick with this set-up for now and am planning on going to the range tomorrow. I don’t anticipate any issues.

NOTE: Installing the striker block safety spring was a mild PITA. Unlike the MC1SC used in the tutorial, the MC2C (or at least mine) has only a tiny little angled hole in the top of the slide in which to drive out and drive back in the roll pin (actually a coil pin) you gotta be really careful when driving that pin out/in through that hole. make sure your 1/16" pin punch has a long, straight driving shaft and preferable is a proper roll pin punch with that little “bump” on the punch tip. The extractor is under a LOT of tension from the extractor spring which flew across the room when the coil pin got driven out enough to allow the extractor to release. The next issue was that the striker block safety/spring would not readily drop out. I had to use a combination of tapping on the top of the slide with the polymer end of a gunsmith hammer and using the plier tips from my Leatherman Squirt to drive/pull out those two little parts. Oddly enough it went back easily. Go figure. I very carefully drove the coil pin back in part way again using the polymer face of my hammer and then with extreme watchfulness tapped the pin in the rest of the way with that 1/16" punch. You may wish to drive the pin in from the inside of the slide vs. the outside. I didn’t have a third or fourth hand :rofl: but that might have helped.