Instructions unclear, I've built another 16 inch gpr in 556

4.5 inches is totally long enough, definitely fine, kinda huge actually

Brass facts consistently reinforcing my opinions is such a serotonin hit

10.5 is the best, because that's what I have, and I'm too broke to buy something else.


Side note: the deer don't seem to care about barrel length, they just fall over ded.

The noveske 300’s that Devgru uses have 10.5 barrels. After a lot of testing they felt they had the best blend between velocity for supers and dwell time for reliability with subs.

Instructions unclear, joining 20" chad gang.

Brass facts for the love of god, please do a .300blk v 5.56 with fair comparisons unlike what garandthumb did on his channel. A 6 inch .300blk barrel for testing was ridiculous

If you need subsonic, go 300BLK. If you need to go shorter than 10.3", go with 300BLK. If you want AK performance with AR ergonomics out of a 16" barrel, go 300BLK. Really, everything 10" and up, it's the AR/AK compromise, and AR gets better and better the longer the barrel gets, but people tend to sleep on 300BLK supers out of longer barrels. Make no mistake, a 16" barrel will put out around 7.62x39 velocities with 125gr bullets.

Brock has been bought out by the Waffle top industrial complex. Reviews paid for by big waffle.

Another lesson in why 5.56 just won't go away.
Also, 55 grain speer gold dot bonded softpoints is like .60-70 cpr in bulk.

8.3” barrel + 7.5” handguard = perfect can fitment

As someone who has a 7.5in 300blk thank you for not giving me buyers remorse

I went with a 10.5 for a few reasons.
Better supersonic performance at over 2000 fps.  Short enough to keep subs subsonic.  Short enough that it's not too long with a can.  And it's the same length as my 10.5 in 5.56 so it's setup the same.

In the end since the cartridge was "optimized" for 9" anything within 2 - 2.5" of that should be fine.  A little longer will get you better super performance and a little more velocity on subs while remaining subsonic.

I dig BF because he doesn't put on a Youtube "celebrity" vibe. Seems like you could meet him for the first time and be like yo you wanna go shoot? And he'd be like hell yeah. One of us.

A 9" suppressed will do great in home defense and it can flex into short range hunting applications. LARPing fantasies aside I think the performance makes it worth adding one of these to the AR collection for most people. Pick up some 115gr Barnes Vortex cartridges and whatever subs you prefer and you will have a handy little brush and home defense weapon.

I run a 7.5 barrel .300blk with my Deadair sandman s and I have no issues, it’s actually one of the nicest rifles I’ve ever built. There’s literally no recoil impulse with the H2 buffer

I just bought a PSA Sabre 8.5” upper in .300 blackout with an adjustable gas block and suppressor ready handguard. Got it on sale for $500. The lower with an HBPDW brace was $500. Got myself a knockoff Badger.

A 10.5in 300 blackout got the same energy on target as A 5.56 in 16in barrel

Just in time for a late lunch, thanks brock

My two “go to” SD/HD guns are my PSA 8.5in suppressed 300blk using 190gr Hornady ammo and or my AP5 Suppressed 9mm using 147gr Hy-Shock ammo.