M*CARBO Brotherhood

Muzzle Brake Install issue. Assistance needed

Hey everyone, first post. Also new to firearms for about 7 months. Very much a newbie and not very mechanically inclined, although I try. But I often wish I just took whatever was broken to a pro.

Purchased a Sub 2000 last week and then several M*CARBO Accessories. I have also watched all videos when doing these installs. The Recoilless Charging Handle where you have to compress the coil was a serious POA. Got it but it took a while.

Today I attempted to install the Muzzle Brake while also using the recommended Barrel Jaws. I again watched the install video. Did everything per the instructions. Cranked it until it got tight, I backed it off > started tightening it again > then backed off > started tightening again as the top of the muzzle brake was underneath (on the bottom side). Then all of a sudden my front sight moved.

I have no clue how to loosen and readjust this. I have removed the Muzzle Brake. The crushed washer is still on. Do I have to take that off? If so, it’s on there good. So how?

Next, how do I get my front sight straight again? There is a nut that the crushed washer was butting up against. Is that how I would readjust?

Here is a picture of how it looks now.


Welcome to the forum @metalshock I’ll bump this post some some of our Kel Tec brothers here can help you.

The crush washer is a one time use as far as I know.

Sounds like you “might” need a M*CARBO jam nut wrench if the nut is super skinny.

Highly Recommended for Properly Mounting your KEL TEC SUB 2000 Gen 2 into a vise and preventing any unnecessary damage to your Pistol Caliber Carbine. Will fit both 9mm and 40cal Barrels for your KEL TEC SUB 2000 Gen 2. The only way to properly install a KEL TEC SUB 2000 Gen 2 Muzzle Brake is with a Crush Washer. First of it’s kind KEL TEC SUB 2000 Gen 2 Barrel Jaws for installing all of your KEL TEC SUB 2000 Gen 2 Upgrades.

Highly Recommend Wrapping your Barrel in masking tape before crushing bare aluminum jaws against the barrel in your vise. This will prevent any unnecessary scratches to your barrel

Do Not Install a Crush Washer Style Muzzle Brake onto your KEL TEC SUB-2000 without this set of Barrel Jaws or you will need to send back to KEL-TEC for repair of part number 102 (which is the Plastic Hinge that houses the barrel). Improperly installing a Crush Washer Style Muzzle Brake could allow the barrel to twist and snap the Plastic Hinge which houses the barrel.


Good luck!


Thanks @MountainHunter
I used a Vise, the Barrel Jaws and put tape on the barrel before attempting the install. But somehow the front site twister as you can see in my picture. I just need instructions on how to get off the Crush Washer and then instructions on re-straightening the front sights. If I have too I’ll bypass the muzzle brake for now until I can get another Crush Washer. Any input to my questions would be greatly appreciated.


Welcome aboard. If the crush washer is still on the barrel, clamp it back down and take a good rubber strap wrench to it. Reduces the chances of damaging barrel threads. The next thing to try would be using some wooden shim or similar soft material to use as a pry bar.
As for the the cantered sight, it looks as if you put a bit much into the break and twisted the barrel on its threads. You may need to clamp the receiver down to straighten that back out. Again, with a strap wrench to protect everything and it clamped, wrench the sight back over. Worst case is send her back to the factory because of the plastic insert for the barrel threads. I hate to see you break that.


Thanks @Thatoneguy
It sounds a bit over my head. I’ll have a friend take a look at your suggestion and see if he can assist. Really frustrated as I did everything that was in the video. I’ll post back if I’m able to get it fixed. If not then I guess it’s off to Kel Tec. Appreciate the feedback.


A few pictures of the crush washer situation could also help.
Your picture does look like the barrel was over tightened.
Let us know how you proceed.

If you can’t figure it out, wait until Monday and contact a tec at M*CARBO.


You are not alone. I tried the muzzle brake install myself… and failed. Took it over to my local gunsmith and with the right tools and expertise he finished up in 5 minutes. He didn’t charge me but I gave him a $10 bill and told him to buy a drink on his way home.


@TexasEskimo yup, that’s what I’m doing later today. Going to a friends house who’s skilled in building guns, and modifications. He believes he can fix it (the now unaligned front sight) and maybe get the muzzle brake on. If not, then I’ll take care of that another day.

The mods I’ve done have been the Muzzle Brake, Bolt Tube Cover, Buttstock Pad, Recoilless Charging Handle, Rapid Deployment Latch and Recoil Buffer. Out of these mods per the videos, the Buttstock Pad went pretty smooth. The RDL, Bolt Tube Cover and Recoil Buffer weren’t difficult except reassembly because the bolt wouldn’t drop all the way. The biggest pain was the Recoilless Charging Handle. Compressing the coil was very difficult. Still have a blister on my thumb to prove it. The video made it seem a lot simpler than it was. The video for the Muzzle Brake I followed step-by-step and ended up with no Muzzle Brake installed and a crooked front sight.


I finally got it all straightened out. The crush washer was so imbedded into the sight lock nut. Just so you guys know, and I posted this above, but I followed the installation instructions to a tee. The muzzle brake never even made it 180 degrees after hand tightening it before the front sight shifted. So bizarre. I went over to a buddies house who is knowledgeable with all things guns. Unfortunately he’s an hour and a half away from me. I walk in and the first thing he says is “you bring the barrel things for the vise” (barrel jaws) and guess what, I forgot them… ugh. So putting the muzzle brake on wasn’t going to happen that day. Our focus was on getting the crush washer off. We tried tapping it with a punch. Heat. Strap wrench. It became loose, but every time it would spin it got tight again. We ended up as a last resort using a dremel tool and knocked away at it until it finally broke loose enough to slide off (see picture of tore up crush washer). Took an hour and a half. Serious pain. I went back yesterday to finish the job. I went ahead and picked up a new front sight lock nut just in case and we ended up using it because the original was scuffed up. Right after the lock nut loosened up… bam, the front sight was able to be re-positioned. We installed the muzzle brake with zero issues. I also picked up the M*Carbo Optic Mount and we installed that too. Adjusted a bit and fired off 50 rounds on his property at a target. Working great. Plan to go to the range tomorrow. Final product pictured as well. Also wanted to say thank you so much for all your feedback and advise. Really appreciate it.


Awesome @metalshock
Glad it worked out for you. Good shooting to you if you get your chance tomorrow :+1:t2:


@metalshock Thanks for letting us know. We all learned something new! :beers: