I'm getting ready to build a 300 blackout with a 10.5 inch barrel.  I was thinking of just getting a thread protector for now.  Is the muzzle flash going to be killer with sonics and subs or what?  Thanks in advance!

I have an 8" 300 BLK upper, currently with no muzzle device "permanently" installed, as I haven't made up my mind if it will be used long term with my Gemtech Quicksand suppressor (requires a mount be rocksett installed on the bbl so it won't easily come unscrewed).  While in good fun, my shooting buddies have commented on its noticeable muzzle blast when using a thread protector.  So, yesterday we did an test of muzzle blast:  thread protector Vs Gemtech Vortex Quickmount.  All 3 agreed that the muzzle blast (while certainly still there) was reduced by having the Vortex Quickmount in place and for nearby shooters, the Vortex flash hider/suppressor mount made it more pleasant.   This was done in daytime, so muzzle flash was not easily seen.  I am assuming that muzzle flash intensity would be similar to the intensity of muzzle blast and that a flash suppressor designed to break up muzzle FLASH would also be good at breaking up muzzle BLAST.  I would therefore recommend you install a flash hider.  An A1 or A2 style 5/8x24 thread one would be the cheapest and do a good job without adding much weight.   Bonus:  would also better protect the muzzle from accidental dings.

I have a thread protector and have not noticed any extreme muzzle flash.


The round is designed to have most of the powder burned before the


bullet leaves the barrel.



Mine has a 9" barrel.








 

this is extremely relevant to my interests - considering building a 10.2" blk and leaving the muzzle bare to thread on an osprey (with subs only)

would be nice if there was a youtube vid of someone shooting supers at night with a bare muzzle...

i've gone complete circle and now use a thread protector only...

Just buy the AAC blackout non mount flash hider (doesn't require to be timed)  just hand tighten it, and just pull it off when you want to thread on your supressor.

not the best idea - loose flash hiders love to come off of barrels

 

I never had any complaints, by I just put an à2 flash hider on until I settled along my suppressor mount.

Yes. There will be significant flash. My 9" barrel rifle will occasionally flash, even with subsonics without a flash hider.