300 Blackout Build Questions
Title: Building a dedicated suppressed 9” .300 BLK for home defense—looking for proven setups and parts recommendations
I’m about to build my first dedicated .300 Blackout AR, and before I start buying parts I’d like to hear from people who have actually put a lot of rounds through theirs. I already bought the upper 9” BCM upper, so I’m mainly looking to dial in the rest of the setup around it.
My goal is reliability above everything else. I’m not trying to build a rifle that does every possible combination of ammo and suppressor. I’d rather optimize it for the roles I actually care about.
Primary role
Home defense
9” barrel
Suppressed
Dedicated expanding subsonic defensive ammo
Reliability is priority #1
Secondary role
Compact backpack/truck gun
Suppressor removed
Supersonic ammo
I don’t care if unsuppressed subs work.
Basically, I’m okay if the rifle is optimized for:
Suppressed + subs
Unsuppressed + supers
and I don’t mind if the other two combinations aren’t perfect.
My questions:
Is this a realistic way to tune a .300 BLK, or am I overlooking something?
What buffer weight and spring are you running on a setup like this? Standard carbine? H buffer? Sprinco? Something else?
Which suppressors have given you the best reliability with subsonic ammo? I’m actually looking for moderate-to-higher backpressure, not the newest low-backpressure cans. My understanding is that the extra backpressure can help ensure reliable cycling with suppressed subs.
If you could buy one suppressor today specifically for a 9” .300 BLK, what would it be and why?
Which defensive subsonic ammo has proven the most reliable in your rifle? Hornady Sub-X? Lehigh? Something else?
If you had to build this rifle again from scratch assuming you already had a 9” upper, what lower components, suppressor, buffer, spring, and muzzle device would you choose?
I’m not looking for theoretical answers. I’m interested in hearing from people who have actually run a setup like this for a while.
Thanks!