M*CARBO Brotherhood

Just Ordered the New Locking Pin

You can still use it for hockey. :grinning: This one is very old and no longer smells of rubber, it was “made in Czechoslovakia”. I needed one while doing some gunsmithing at 2am as ya do (on my CZ 97 B, no less), the puck and my cordless drill were handy…


That one side will have an increased drag coefficient. Unless im facing Patrick Roy, i wouldnt stand a chance. :laughing:


The hole goes through…guess it’s no longer regulation weight… :grinning:

Showing our age a bit there, no one’s faced him since 17 years ago… :rofl:


I watched the installation video. First of all, I’m buying a new recoil spring from Kel-Tec; just in case I really mess up the installation.

But it brings up a question: Wouldn’t it be easier if M*Carbo just sold the whole recoil spring complete with the modification? That would make installation super simple.

Maybe someone can put this in M*Carbo’s “suggestion box”.

Forget about the cost for now. I’m mostly interested in the mechanical challenges to making the whole recoil spring with the modified locking pin.

Here’s another question: Could M*Carbo perhaps include additional “tools” for installation. For example, a device that is sized just right for compressing the recoil spring. Just squeeze and pull. And of course, adding a perfect 3/8" block with a hole in it can’t hurt. Needless to say, the more stuff you pack in the kit, the larger the package and associated mailing becomes.

All said, the installation video is great except it begs these two questions: Why not make a modified recoil spring in the first place? If not, why not develop some tools to make the DIY job a little easier?

Thanks in advance,



They’ll install it for you if you wish.

No need to worry about it falling out, just that the neck where the recoil spring seats is a potential spot for failure. If it fails, they’ll send you a new one with a thicker neck and toolless locking pin.


My locking pin is in transit. I couldn’t find anywhere on the site about them putting these together. Any suggestions?




@AV8R Thank you Nigel. It appears that everything is a minimum of $95/hour. I best get my tools together. Lol.


Yeah, not much is free these days.
Just looking at the video, it doesn’t appear too difficult to install


I just don’t want to damage my spring. So I may proactively procure a backup first.
You know the saying… “Two is one, and one is none”.


Got mine in today. Install was Relatively easy. I still have both my eyes lol.


Mine arrived today and was installed with minimal fuss. It helps to have an extra pair of hands.

Here is one tip that was not explicit in the Video. Do not compress the recoil spring from the top. The lower coils will become too tight making it difficult to insert the provided hex wrench. Instead, grab the spring at a point you can compress below where the wrench needs to be inserted; i.e. the top of the lower guide rod piece. The coils below your grip will be tight, but those above will be loose enough to easily insert the wrench.

Replacing the recoil spring and engaging the notch is still a little fidgety but much improved over the previous option.


tool-less spring tool—use a 2nd allen wrench just below mid-point and use that to compress the spring sliding it 1/2 way through the spring. Easy 2min install.


It whistles when you crank up a one-timer! :laughing:


Now that would be fun !


I had the same thought , but I just put mine in and it took me less than a minute. Super easy!


I was hoping for a heavier spring to go with the pin.

A guy on FB used his buttstock to hold the spring instead of a bench block. Not sure what his name is on here, but all credit goes to him.


Springs and guns can be like “Goldilocks & the Three Bears”. Too much k-factor; too little; just right.

The manufacturers make these “just right”, but when you put a mod like this on the firearm, there can be a “loss of tuning” in the motion of the machine. I’m glad we have a forum like this. I haven’t seen anyone say they’ve had a problem.

With that said, I not only bought a spare spring (from Kel-Tec), but also two factory charging handles. I did that as a precaution/contingency. I also did it in case I messed up the spring alteration. From what everyone is telling me, it isn’t that hard.

I also saw someone used the hole in the butt stock as his bench block. (Thanks DocA!) Great idea! That solves one item.

A true “firearms hobbyist” likes to tinker with things like this. It’s one of the reasons I like the hobby. Tinkering with firearms takes a lot less room and resources than tinkering with motor vehicles. Just my opinion! (Some of you MUST like tinkering with cars! That’s a whole nuther thing for forums elsewhere.)

Just so you know (I don’t think I mentioned this in my original post), I have broken TWO factory charging handles on my Kel Tec Sub 2000. The first time, it broke because the charging handle lock sliced the handle every time I used it. After a “death from a thousand little cuts”, it just broke.

The second charging handle broke after 1000+ rounds; just from cycling. Let me know if you (or anyone) have had these problems. Moreover, I hope this problem doesn’t crop up with the MCarbo modification. My guess is that MCarbo knows about this and has chosen materials that are more robust.

The Sub 2000 is a fun firearm to shoot. It deploys faster and is lighter than its Ruger competitor. It is also better balanced. I have also found it a bit delicate. These 3rd party modifications can (I hope) eliminate some of the “weak links” in the machine.

Thanks for the comments everyone!

C ya,


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