300 blackout flash hider question.

[themixr]

I recently built a 300 blackout, but can't find a flash hider. I ordered one but its too big for the barrel, I tried my 5.56 birdcage, its the right size but the threads are wrong? And help would be appreciated.

[mif_slim]

You would by a 308 flash hider.

[themixr]

Any idea what thread that is?

[mif_slim]

5/8 24.

[ar15barrels]

What thread is on your barrel?
Different manufacturers use different specs...