General purpose .300 Blackout barrel length?

[bravo7]

There’s a fair amount of information published that suggests 9” is the optimal barrel length for 300 BO. I believe they also state it needs at least 8 or 8.5” to get a complete powder burn. I’m sure one could debate this all day long. So take it for what it’s worth. I built a 9” 300 BO SBR and only run it suppressed. I’ve had great result using Gorilla 220 SMK subs and Barnes 110s. Initially, I ran a few hundred rounds of Freedom Munitions 208 AMAXs and also experienced no problems. I don’t use an adjustable gas block either......it’s not necessary.

[SeriousStudent]

There’s a fair amount of information published that suggests 9” is the optimal barrel length for 300 BO. I believe they also state it needs at least 8 or 8.5” to get a complete powder burn. I’m sure one could debate this all day long. So take it for what it’s worth. I built a 9” 300 BO SBR and only run it suppressed. I’ve had great result using Gorilla 220 SMK subs and Barnes 110s. Initially, I ran a few hundred rounds of Freedom Munitions 208 AMAXs and also experienced no problems. I don’t use an adjustable gas block either......it’s not necessary.

That essentially mirrors my experience as well. I have a SOLGW 9" medium contour barrel on pistol brace lower. It shoots really well with the Barnes 110's. As mentioned, it is fun and stupid quiet with the subs.

[DocGKR]

For a "general purpose" .300 BLK carbine, I prefer a 16" barrel, as it offer roughly equivalent performance as a standard 7.62x39 mm AK47/AKM and is legal in all states with no NFA hassles.

For a compact shoulder fired CQB/PDW type .300 BLK weapon, a 9" barrel is a good choice.