Trigger spring upgrade: having some trouble

I bought the trigger spring kit and bushing to upgrade my new sub 2k. Watched all the videos I could find. I think there’s something wrong with the trigger because I can’t seem to get it to lock back and dry fire. I also did the double finger charging handle and a foregrip (though I doubt that has anything to do with my issue here…).

Had a heck of a time getting the charge tube assembled after I did the springs but finally got the hammer to lock and it slid together. It almost seems like the tigger bar isn’t positioned right but it looks exactly like all the videos.

Any advice on what to check?

I bought the gun because my wife hates shooting my AR and the kid’s .22 isn’t any fun for anyone over 12. We already have a Sig P320 XC with a Holosun optic and light/laser combo hanging off the front, a bare bones Kimber Micro 9 that my wife loves, a Browning 1911-.22, a Security Six (serial number 100,000- kinda neat), and some other fun stuff. The AR started as just an M&P Sport II and somehow ended up being a 25-600 yard beast.

Just saying all that to say this isn’t my first gun nor is it the first I’ve taken apart but it is the first I can’t seem to figure out.

Any pointers? I’d like to take my family to the range tomorrow afternoon since I’m the only one who’s shot it yet. That was about 2 days after I got it and only to sight the red dot I put on it. The irons, from the factory, are every bit as good as any red dot on this thing though. At 50 yards it was hitting just about 1/4" low from the factory settings. To me that’s about perfect


Welcome !
I think we all have had a problem, one time or another, putting it all back together. My go-to video for field stripping and reassembly is this one: Ultimate KEL-TEC SUB-2000 M-SERIES Build! All KEL TEC SUB 2000 Accessories & Upgrades by M*CARBO! - YouTube

Give it a try, take your time, and most importantly, make sure everything is seated properly before attaching the two sides. After that, getting the hammer to reset is tough. Once you hearing it click, you’re pretty much done.

Good luck !


Well I found out I somehow had the hammer on upside down but it’s still not right (oops. Must’ve been tired the last time I assembled it). It’s cocked, the slide works now, but pulling the trigger doesn’t do anything. Probably back to the plastic trigger pin not seating right again pushing the trigger bar up and away from the hammer release thingy.

So instead of tearing it apart for the 87th time I decided to throw more money at it. Took it to a local shop where we tried to fix it and still didn’t have success. But he has a guy who’s a big Sub-2K guy that’ll figure out what I’m doing wrong. While he’s in there I’m having him do the trigger and trigger gaurd, trigger bar, screw set, hammer pin, and ramp. I figure that way almost everything internal is done and hopefully I won’t have the pleasure of taking it completely apart again for a long, long time.

I still can’t believe some of the factory shortcuts inside it. The springs themselves and how they rest against stuff like the screw guide baffles me. It’s like they took a toy gun, threw a real barrel and charge tube on it, and prayed it never came apart!

I hate to say it but M-Carbo should really consider making a complete aluminum grip for it just to make the gun durable. I know the plastic is light and all but…

Makes me leery of buying the more expensive Kel-Tec guns. My Sig P320XC was the same price as the Kel-Tec and there’s none of that cheap stuff going on inside it. My AR was only $200 more but it’s almost all metal and I can tear it down and put it back together in about 10 minutes. Takes that long just to get the handle apart on this thing.

I know this is the same stuff everyone here has gone through. I’m hoping with the upgrades I’ve thrown into this thing it’ll make me forget this initial experience. I only put 40-50 rounds through it so far and it was great to shoot but felt cheap. I’m hoping what I’ve done fixes that feeling.


@Gbauer The Sub 2000 is a cheap gun. I’ve said before this is not a firearm built to last. It’s a novelty. I do believe it is a useful and interesting design. I wore two of them out. And very affordably replaced them with the Gen 2 model.

The S2K is reliable and reasonably accurate within its intended range. It does run better with the MCarbo upgrades. S2K owners spend their hard earned money on the MCarbo upgrades because they value the unique design. Not because it’s an heirloom quality firearm they want to invest in.

Engineering-wise I don’t see a big difference between the Sub 2000 other polymer firearms in the same price range. I’m not sure the comparison to the Sig is legit. Apples and oranges. The 320 is a modular design pistol. 90% of the gun is inside the FCU.

I do get what you are saying… for another 250 bucks you could have had a low end AR. But then you would just have another boring low end AR that doesn’t fold up. No fun at all. Putting things into perspective… another 250 bucks is about 40% more than you probably paid for the Sub 2000. So applying that principle, if you bought a P320 for $500, you could have spent $900 and got a better gun.

I have been a clay shooter since I was a kid. I can compete effectively with a decent Beretta or Browning shotgun that costs $2500. If I sacrifice weight, balance and overall comfort I can do the same with a $700 shotgun. Or I can sell a kidney and shoot a $15,000 Krieghoff. It’s like golf. A set of clubs that cost $4000 wont make anyone who isn’t a pro a better golfer.

In summary, I say enjoy the Sub 2000 and accept it for what it is. It’s wonderfully cheap, unique and fun to shoot and with proper care it will love you long time.

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Did you try tightening/or loosening that screw right above the trigger that runs threw the body? About 1" or so above the trigger Try tightening and then loosening. Chris from MCarbo video has a part on the video where he has some problem with the trigger, and adjusting that screw fixed it. Also I had a problem on my new Sub 3/2022 where the trigger pulled like it was in safety mode except made just made a little click sound when actually in fire position. I Turn the screw in tighter and it went to a normal function.

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It’s fixed. First off I somehow had the hammer upside down. That was a big part of my problem obviously. Not really sure what else they found but the guy who fixed it installed basically everything MCarbo makes for the internals. Just shot 33 rounds through it and it’s exactly the way it should have been from the factor to begun with. Awesome gun now!