M*CARBO Brotherhood

Where Can One Get A Jam Nut For The 9mm SUB2K Gen2?

I need your help Brothers.

I have a Sub2k Gen2 9mm. The barrel on this firearm came with a single jam nut to lock down the front sight but its also doubling as a thread protector since it covers the threads completely. It is 0.4250" in length.

I have already have the MCarbo muzzle brake with its own exclusive jam nut and want to install it.

The problem is I cannot seem to find a jam nut that I can use to lock down the front sight. Also I want to make sure the jam nut is not too long since I want to have room to install the Mcarbo muzzle brake and its jam nut.

Earlier I had applied rocksett on that jam nut/thread protector, I think I read earlier I can simply spin this off? I had applied 25 ft pounds of torque on it so its not a whole bunch of torque I have to undo.

Any help or link would be most appreciated. Please can someone point me to a jam nut with maybe .190" thickness for our Sub2k?

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The Frt Sight has a Allen head Pinch Screw Also, I had Issue’s with getting the muzzle brake Timed correctly so I went to Joe Bob’s Outfitters and got a AR shim kit 3 shim’s included in kit $5.00 went with the Thick Shim no problems stays tight and Timed Perfectly, 500 rounds and counting.Hope this helps.

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@goretro77 Use the muzzle brake with a shim kit as the jam nut for the front sight. With the right shims you can time the brake just right to center once tight and it will then hold the front sight as well. Delete muzzle brake jam nut as well. Why have one jam nut for the sight and then another jam nut for the muzzle brake?

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I did notice the allen head pinch screw which I guess works with the jam nut and I’ve had not issues with the front sight moving on me. I’d like to continue using a jam nut and torque that on the front sight when I install MCarbo’s muzzle brake.

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@goretro77 My Gen2 did not have that little allen pinch screw and I had to really heat gun the front sight and jam nut to get it to come off.

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Very true, I didn’t think of using a shim kit.

Is this what you did and where to go for the shim kit?
Thank you.

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@goretro77 I have installed the Red Lion folding front sight which does not need a jam nut, it has it’s own clamp screws plus a set screw but before I had installed that I had the stock front sight with just the muzzle brake tightened against it using shims to get it centered. I believe I got them from Brownell’s or on Ebay.

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or you can go with the AR crush washer, just mark your spot and do not over torque, once crusher there is no going back, ya replace it and try again…
Brownells, P/N 080-001-252WB $2.99 each www.brownells.com

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Thanks guys for the replies and good advice!

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I use the shim kit from Brownells. It comes with 8-10 shims. I posted the kit in the muzzle brake thread. Ended up using .016" on mine been on for over 2000 rounds and no issues.

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