Looking to build .300 blackout upper

Paperpounder · Mar 13, 2014

1st timer ...

I think I am gonna go with the Daniel Defense s2w in 16" in carbine length gas system.

Question is what diameter gas tube and gas block to you guys recommend?

Other specs so far
BCM upper receiver
BCM KMR13 rail
BCM BCG

Thanks

CrawfishStu · Mar 13, 2014

I put a wilson adjustable on mine.

armed ferret · Mar 13, 2014

Gas tubes come in varied diameters? When did that shit start?

Paperpounder · Mar 13, 2014

armed ferret said:
Gas tubes come in varied diameters? When did that shit start?

Maybe they don't, I just was reading about during my research.

BradMacc82 · Mar 13, 2014

Personally I'd go pistol length gas.

Oh wait, I did. On both builds.

FlatsFlite · Mar 13, 2014

The diameter of your gas block will be determined by the diameter of the barrel you choose. No 2 ways around that.

Edit: I just looked that up. Seems to me, your gas block will be a .750.

Manufacturing # / SKU
16"_Carbine_1:8_300BLK_Barrel

Restricted Shipping
Yes

Barrel Configuration
No

Barrel Length
16"

Manuf. Process
Cold Hammer Forged

Twist Rate
1:8

Muzzle Thread
5⁄8×24 TPI (Threads Per Inch)

Material
Chrome Moly Vanadium

Outside Finish
Salt Bath Nitride

Diameter At Gas Port
.750″

Chrome Lined
No

Barrel Extension
A4

Profile
S2W® [Strength 2 Weight]

Gas System
Carbine Length

Caliber
300 BLK

Manufacturer
Daniel Defense

Flipz · Mar 13, 2014

BradMacc82 said:
Personally I'd go pistol length gas.

+1

BradMacc82 · Mar 13, 2014

OP, more than likely you'll be using a .750" gas block. I don't recall seeing any 300BLK barrels in .625" or .930" gas block seat diameter.

They could be out there, but most all I've seen are .750" on the gas block seat.

Paperpounder · Mar 13, 2014

FlatsFlite said:
The diameter of your gas block will be determined by the diameter of the barrel you choose. No 2 ways around that.

Edit: I just looked that up. Seems to me, your gas block will be a .750.

Manufacturing # / SKU

16"_Carbine_1:8_300BLK_Barrel

Restricted Shipping

Yes

Barrel Configuration

No

Barrel Length

16"

Manuf. Process

Cold Hammer Forged

Twist Rate

1:8

Muzzle Thread

5⁄8×24 TPI (Threads Per Inch)

Material

Chrome Moly Vanadium

Outside Finish

Salt Bath Nitride

Diameter At Gas Port

.750″

Chrome Lined

No

Barrel Extension

A4

Profile

S2W® [Strength 2 Weight]

Gas System

Carbine Length

Caliber

300 BLK

Manufacturer

Daniel Defense

10-4 thanks for clearing that up.

Russ D · Mar 14, 2014

Pistol gas for sure, but I only have 10" and shorter 300 blk barrels.

BradMacc82 · Mar 14, 2014

Russ D said:
Pistol gas for sure, but I only have 10" and shorter 300 blk barrels.

After seeing how well a pistol length 16" Noveske behaved on a previous build, it's a no-brainer for me.

Ran sweet on a 12.2" Noveske also.

View attachment 113596

They were fun, I may build another (pair) later on.

Russ D · Mar 14, 2014

The fun part about 300BLK is that it doesn't lose much velocity when you run a short barrel. I still may build a 16"er but I would also be tempted to just go with the 6.8 at that point. Here's my 10" Noveske

BradMacc82 · Mar 14, 2014

Russ D said:
The fun part about 300BLK is that it doesn't lose much velocity when you run a short barrel. I still may build a 16"er but I would also be tempted to just go with the 6.8 at that point.

Originally the 16" was built for deer duty, and provided the shots were in my comfort range - it did quite well in that role.

My pending tax stamp is for a 300BLK SBR, so I'll build another to satisfy that stamp.

The 16" was fun to explore the accuracy potential of the round. That upper would out-shoot me the majority of the time.

Russ D · Mar 14, 2014

Out of curiosity is the 16" more accurate? Other than being able to shoulder it and optic choice, it shouldn't be any more accurate that the shorter barrel.

BradMacc82 · Mar 14, 2014

Russ D said:
Out of curiosity is the 16" more accurate? Other than being able to shoulder it and optic choice, it shouldn't be any more accurate that the shorter barrel.

I hadn't been able to stock the 12.2" to really compare, but the 16" would do MOA and better all day when I could keep myself up to the task.

The 12.2" as a pistol, had no problem picking off clay pigeons at 105 yards with an Aimpoint PRO mounted, consistently.

Neither one ran much factory ammo, predominantly handloads.

ETA: The 16" was only wearing a 2x7 muzzleloader scope, so I considered MOA or better to be absolutely great for the underpowered optic and thick reticle.

Flipz · Mar 15, 2014

Russ D said:
The fun part about 300BLK is that it doesn't lose much velocity when you run a short barrel. I still may build a 16"er but I would also be tempted to just go with the 6.8 at that point. Here's my 10" Noveske

An 8.2" Noveske barreled 300blk pistol (future SBR) that I built last week.

Russ D · Mar 15, 2014

I like that pistol buffer tube. Which is it? When I built mine the RRA was pretty much the only game in town.

iHasCrabs · Mar 15, 2014

Russ D said:
I like that pistol buffer tube. Which is it? When I built mine the RRA was pretty much the only game in town.

Phase 5 tactical

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Looking to build .300 blackout upper

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