M*CARBO Brotherhood

S2k Gen 2 Loose When Unfolded

Good afternoon all.
I have a sub 2k that I have put all of the mcarbo aftermarket parts on as well as red lion rotating hand guard. Question I have is when the carbine is unfolded and clicks into the open position there is a little movement up and down between the 2 half’s still tight on the top at the pivot point but the bottom will open and close ever so slightly. I don’t remember it doing this before and seem like it shouldn’t. Any thoughts. Thanks Krank.


@kranker1450 I have read posts on KTOG were they used shims (such as cut up credit cards) to address this issue.

Other than that I don’t run the Red Lion so can’t help you too much.

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It is the same from the Handgaurd back. All of the barrel mounting and pivot parts are all stock Keltec so that shouldn’t have changed. I am little confused as to what changed. Ever if I put the stock trigger guard on it is still loose.

Thanks Krank

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@kranker1450 I am confused…was hanguard tight before and now is lose after installing MCARBO parts? You did loctite all the screws on the handguard right?

@kranker1450 The barrel locknut part #103 may have loosened up when you swapped handguards. Should be snug but not overly tight. Kel-Tec did use a thread locker on this so be aware.

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The handguard is tight. It is the whole barrel assembly. After it pivots open and clicks in place it has a little slop left in it. So you can start to lift up on the assembly like you are folding it back up. It will move some before stopping against the trigger guard lock. The barrel is tight to the block, it does not rotate.

If that makes sense. SO after you open it instead of it being solid with no movement between the 2 halfs you can lift up on the front half as if you were to fold it up again and it will move ever so slightly before catching the trigger guard. If you pull the trigger guard it will fold up like normal.


Two of my favorite words are now your friend:. Lifetime Warranty. Gotta love Kel Tec.

I figure it is something extremely minor, but in the location you describe, I hesitate to play a guessing game. That said, are you absolutely certain the trigger guard and it’s spring were located correctly?


Went through it. Take off forgrip and you’ll tighten the round barrel nut. There’s a large flat plate that it tightens against with a washer between. There’s info out there but the plate has to be oriented correctly or it won’t tighten correctly. I had to run the nut tight, then loosen, several times to clear the threads enough to tighten.
Goal is to tighten to the point the trigger guard will just snap closed when locking gun into firing position. I actually tightened mine just a hair passed so i have to bump trigger guard closed.


I’m having the same issue. I’m about to install a new trigger so hopefully I can get it squared away while it’s opened up.


Thanks for that info! I’ll give it a go tomorrow.

Sorry for digging up an old thread here but found this one when searching for a solution to an issue with my Gen2 S2k.

@4QBarry Just wondering if you found what @Gilligan369 described was your issue and you were able to resolve it. I haven’t torn my forend down yet but believe my Subby is suffering from this issue, it’s exhibiting a tiny bit of play when unfolded and locked. At first I thought maybe I did something wrong when installing my MCARBO trigger kit and guard, though I felt relatively confident in my work. I even went so far as to crack it back open and reinstall the factory trigger guard to see if the play was still there…and it was.


Don’t be sorry @chilipepper! Oldies but goodies. Lotta knowledge and experience exhibited here over last year and a half. Shows you searched for the answer first, totally pro👍


@Boomchucker Yeah, I guess I didn’t want to be “that guy”. :grinning: I figure you’ve got to do a little homework first, though it’s easy to miss things sometimes. There is a lot of knowledge to be had here, a good resource for sure.

I think I lucked out finding this thread rather quickly as what @kranker1450 and @Gilligan369 described sounds a lot like what I’m seeing with my S2k. If I get a chance this weekend I might just have to crack open the forend and see what’s what.

Even blind squirrels find nuts every now and then… :laughing:


Is the screw that is on the pivot tighten down? Perhaps loctite it?


Nah, the screws are all good. Speaking of screws, I did that upgrade at the same time as well as the trigger bar, mag release and feed ramp. I double and triple checked everything I messed with for the install and couldn’t find anything that seemed to be off. Even walked away from it for a day or two to clear my head, as we all know sometimes it’s the simplest things and they’re right in front of us the whole time. Once I swapped back to the factory guard and the play was still there, I felt pretty confident that it wasn’t something I had done wrong during the installation. That said, I was still at a complete loss as to the cause…Brotherhood to the rescue! :+1:


No bones boys…my barrel nut was tighter than a bulls a$$ in fly season and I’ll be damned if I can budge it. Obviously I don’t have the spanner wrench they use at the factory, so I used a punch and hammer to get it to rotate in either direction and ended with fractured flutes on the nut. I’ve used this method many times before in other applications and it worked a charm. But it will not move and I’m not happy. I’m sure the lockup was sloppy from the factory, problem now is I’ve got a firearm loaded with aftermarket parts and a damage nut to boot. I doubt Kel-Tec will honor the warranty at this point. :rage:

Appreciate the info here, regardless.


you got a gen 2 sub correct?look at the ears where the pivot pin goes thru on the inner part of the pivot. My LGS showed me one that split on the inside pivot, just enough to make it wobbley but not enough to make it fall apart… .Kel -tec is excellent about honoring their warranty with aftermarket parts and skuffs. call em


@GOBLIN Yep, it’s a Gen2 Subby. Are you talking about the pivot for the trigger guard or pivot for the forend? I didn’t notice anything at either location when I had it apart but it was a few months ago. She seems snug at all the joints and folds fine, but when it’s locked open, I can grab the forend/barrel assembly and move it back and forth a little, enough that it concerns me. I’ll give them a call on Monday, hopefully they’ll help me out without too much guff. Fingers crossed. Thanks for the reply.

Actually a little pissed at myself, I’m good with tools and fixing things but that little bastard of a nut put up a hell of a fight. Seems like everyone else’s was loose or just hand tight when they got into it…but not mine…


define back and forth. with it locked in the open position, is the play side to side or up and down. I was referring to the pivot point at the barrel, but check the spring and latch pivot as well


There’s play in the direction of the red arrow, as if the trigger guard needs a little more length on the locking lug in order to tighten it up. This happens with both the stock guard as well as the MCARBO. I’d shoot video of mine but I’ve already got the forend removed. Sorry for the previous bad choice of words to describe the movement.