Kel-Tec RDB-C muzzle brake help

[Bigboss4198]

[baih777]

Are you saying even with a crush washer. Threads are still showing ?

[Sparrow Dynamics]

You should not put a birdcage flash hider on a featureless rifle. Maybe you did it just to check the length of threads.

Measure the length of threads on your barrel. The thread length on a typical AR barrel is 5/8". So, a thread protector should have at least that much of threads to cover it. We make one that is that long, and then has an extra 1/8" of length to protect the barrel crown. That extra 1/8" does nothing to reduce or redirect flash in case any are wondering. A muzzle brake is timed with shims, a crush washer, or a jam nut. Crush washers tend to add an extra .1 to .125" behind the muzzle brake, and jam nuts about the same or a tad more. Shims are minimal and don't add to the length, but are mainly for clocking the brake.

[Bigboss4198]

Are you saying even with a crush washer. Threads are still showing ?

[dfletcher]

Yes. I’ll post some pics

I have the same rifle - no idea why they decided to have that extra shoulder there, makes no sense to me either.

Previous thread on the issue, with some suggestions:

https://www.calguns.net/calgunforum/showthread.php?t=1498409

This jam nut has a collar on it, will cover the smaller inner shoulder:

https://www.ebay.com/itm/LN5-REX-223-five-five-six-1-2-28-USA-made-Steel-Muzzle-Brake-Jam-Lock-Nut/153738358788?hash=item23cb853004:g:lUIAAOSw9IpX0Xw-

Don't know if it will slip over the outer shoulder, IIRC that's .750 diameter. It does add some length, as opposed to a 5/8 split washer.

Adding jam nut or split washer is probably an accuracy no-no, I doubt it makes any difference on the KelTec. Hasn't made any "minute of tin can" difference that I can see.

[Bigboss4198]

I have the same rifle - no idea why they decided to have that extra shoulder there, makes no sense to me either.

Previous thread on the issue, with some suggestions:

https://www.calguns.net/calgunforum/showthread.php?t=1498409

This jam nut has a collar on it, will cover the smaller inner shoulder:

https://www.ebay.com/itm/LN5-REX-223-five-five-six-1-2-28-USA-made-Steel-Muzzle-Brake-Jam-Lock-Nut/153738358788?hash=item23cb853004:g:lUIAAOSw9IpX0Xw-

Don't know if it will slip over the outer shoulder, IIRC that's .750 diameter. It does add some length, as opposed to a 5/8 split washer.

Adding jam nut or split washer is probably an accuracy no-no, I doubt it makes any difference on the KelTec. Hasn't made any "minute of tin can" difference that I can see.

[Bigboss4198]

I have the same rifle - no idea why they decided to have that extra shoulder there, makes no sense to me either.

Previous thread on the issue, with some suggestions:

https://www.calguns.net/calgunforum/showthread.php?t=1498409

This jam nut has a collar on it, will cover the smaller inner shoulder:

https://www.ebay.com/itm/LN5-REX-223-five-five-six-1-2-28-USA-made-Steel-Muzzle-Brake-Jam-Lock-Nut/153738358788?hash=item23cb853004:g:lUIAAOSw9IpX0Xw-

Don't know if it will slip over the outer shoulder, IIRC that's .750 diameter. It does add some length, as opposed to a 5/8 split washer.

Adding jam nut or split washer is probably an accuracy no-no, I doubt it makes any difference on the KelTec. Hasn't made any "minute of tin can" difference that I can see.

On the thread you posted. Where did you find a 308 lock washer?

[dfletcher]

On the thread you posted. Where did you find a 308 lock washer?

Pretty sure it was EBay. Searched "5/8 ID split lock washer" and they came up. Screwed up the first time and didn't include the "ID" (Inside Diameter) spec and ended up with outside diameter ones.

[Gregchico]

I wound up cutting off the shoulder of the factory piece and using a short, standard brake.
I have no idea why they did that either....

[baih777]

That works.

[Bigboss4198]

I wound up cutting off the shoulder of the factory piece and using a short, standard brake.
I have no idea why they did that either....

Did you weld that piece into that tapered shoulder or did you just cut it and slip it over and used a crush washer and brake?

[Gregchico]

Did you weld that piece into that tapered shoulder or did you just cut it and slip it over and used a crush washer and brake?

I just cut off the shoulder of the factory piece and slid into place. I had to install the crush washer backwards to make it fit properly.

Edit to add: You will get attention at the range with this rifle and others wanting to try it out (at least I do), you just don't want the wrong kind of attention from the wrong people. Just what ever you put on the end of this rifle, make sure it is a muzzle brake, not a flash hider.

[Bigboss4198]

I just cut off the shoulder of the factory piece and slid into place. I had to install the crush washer backwards to make it fit properly.

Edit to add: You will get attention at the range with this rifle and others wanting to try it out (at least I do), you just don't want the wrong kind of attention from the wrong people. Just what ever you put on the end of this rifle, make sure it is a muzzle brake, not a flash hider.

[TRAV1S]

Hey, just came across your post. I also have an RDB Charlie, I designed and made my own muzzle brake out of 303SS and 1215 steel then oil quenched to blacken them. PM me if you're still looking to put something on that barrel. I want to make more since there isn't a market for them.