AR-15 300BO, 16" barrel, what gas system?

[freebird]

I've read opinions for both pistol and carbine length gas systems on a 16" 300BlackOut barrel. Both barrels are available, but it seems carbine length is more common. (Finding either in HBAR isn't trivial).

Is there a strong reason, or opinion, or experience, for pistol length vs carbine length?
Does it matter at 16"? (If not, that'd help, cause it would make finding an HBAR in stock easier).

It won't be silenced, if that matters.

 

[BUFF7MM]

I run a carbine length with my 16" and supers with no cycling problems, I've never dealt with the pistol length gas. I'm not much help I know.

 

[freebird]

Experience counts more than opinion. Thanks!

 

[BradMacc82]

Originally, the 300BO was optimized for a pistol length gas system - due to the use of subsonic ammunition.

It seems a lot of outfits have finally started getting the gas port diameter correct for reliable operation with carbine length gas - even with subsonic ammo. Which is better, could be debated I guess.

Personally, I've always opted for the pistol-length gas on my 300BO uppers, and adjustable gas-blocks (never know when the desire to suppress will override the bank account). I've never had any issues that weren't induced by the user - or by development loads I was testing.



12.2" 300BO and 16" 300BO.

Both shot fantastic, both are in new homes.

 

[Boom Boom]

I've read opinions for both pistol and carbine length gas systems on a 16" 300BlackOut barrel. Both barrels are available, but it seems carbine length is more common. (Finding either in HBAR isn't trivial).

HBAR issue only applies to .223/5.56. Other calibers are cash and carry regardless of barrel profile.

 

[retafshooter]

One MSD IP says this...

"1:8 Twist with Pistol Gas System (for better cycling of subsonic ammunition)"

http://www.shop.tomkatammo.com/product.sc?productId=64&categoryId=13

TomKat Ammo, They specialize in 300 BO and Subsonics.

 

[freebird]

HBAR issue only applies to .223/5.56. Other calibers are cash and carry regardless of barrel profile.

I've read so many varying opinions on legality of building a 300BO; HBAR vs non-HBAR. I had decided on HBAR.

I didn't even think to ask what the FFL's were doing.

I'll talk to Engage this week. Thanks!

 

[outrider58]

"1:8 Twist with Pistol Gas System (for better cycling of subsonic ammunition)"

http://www.shop.tomkatammo.com/product.sc?productId=64&categoryId=13

TomKat Ammo, They specialize in 300 BO and Subsonics.

Agreed. OP, while you're by Engage, TomKat is just 10 minutes up the road(hint, hint).

 

[freebird]

First, stopped by Tomkat. Nice little place! They took time out to show me some of their builds. Very nice to talk to. They'll likely get some of my business.

Back to the HBAR 300BO question:

Engage:
They stated they will not sell non-HBAR 300BO full AR15 rifles, saying it's a grey area of the law not yet defined.
They also stated I needed an HQL to do the paper work for an SBR in MD. Odd.

 

[Sticky]

I've read so many varying opinions on legality of building a 300BO; HBAR vs non-HBAR. I had decided on HBAR.

I didn't even think to ask what the FFL's were doing.

I'll talk to Engage this week. Thanks!

I think that is prudent, since there are some gray areas... I run pistol gas on my 300, but it's only 10.5". I would run pistol length gas if my primary usage would be subsonic ammo, suppressed or not on a 16" bbl. The added barrel length really does not add much to the 300AAC cartridge, but reliable cycling with lower powered loads is important for me. You can probably run carbine length gas just fine with most full power loads in lighter supersonic ammo.

 

[outrider58]

First, stopped by Tomkat. Nice little place! They took time out to show me some of their builds. Very nice to talk to. They'll likely get some of my business.

Back to the HBAR 300BO question:

Engage:
They stated they will not sell non-HBAR 300BO full AR15 rifles, saying it's a grey area of the law not yet defined.
They also stated I needed an HQL to do the paper work for an SBR in MD. Odd.

I would assume that's for one of their built SBRs( I believe they are considered pistols by ATF and rifles/pistols by MSP). If you planned to build your own SBR, you shouldn't need an HQL. Just a stamp prior to the building(unless things have changed again...).

 

[freebird]

[/B]

I would assume that's for one of their built SBRs( I believe they are considered pistols by ATF and rifles/pistols by MSP). If you planned to build your own SBR, you shouldn't need an HQL. Just a stamp prior to the building(unless things have changed again...).

I was definitely talking about a build.

 

[Rhino]

I built two 300 bo's, the rifle was a 16" m4 profile 1/8 twist carbine gas. Never had any issues with cycling subs, although it always had a suppressor on it. At the cost of ammo seemed silly to shoot without it. I repurposed the rifle back to 556 so the 300 bo barrel is just collecting dust. It has a 51t hider for a sdn can. If interested it would love a new home for a very reasonable price.

 

[jawn]

I was definitely talking about a build.

Self-build or Engage-built? They do custom SBR builds for folks on Form 4s with some frequency.

 

[freebird]

At Engage, there was a lower receiver laying in front of me on the counter. I asked, for informations sake, what it would take if I wanted to build an AR lower into a pistol or SBR. The salesmen told me. And when he said SBR, he said an HQL was required. I said "an HQL is needed for an SBR build, but not for a pistol build"? He said yes.

 

[DaemonAssassin]

From personal experience with pistol and carbine length gas systems, I'd go pistol length, due to the cartridge being designed around that gas system length. My setup is pistol length gas and will reliably cycle supers or subs.

 

[ap1]

definitely pistol length

I've read opinions for both pistol and carbine length gas systems on a 16" 300BlackOut barrel. Both barrels are available, but it seems carbine length is more common. (Finding either in HBAR isn't trivial).

Is there a strong reason, or opinion, or experience, for pistol length vs carbine length?
Does it matter at 16"? (If not, that'd help, cause it would make finding an HBAR in stock easier).

It won't be silenced, if that matters.

At TomkatAmmo/TKDefense our experience has led us to use the pistol length gas system and HBAR barrels exclusively. This combo can take anything that you can throw at it and trust me, our 110 gr Vmax 300AAC at well over 2400fps are pushing the guns limits. Our 208gr subsonic ELD and AMAX bullets cycle flawlessly but MORE IMPORTANTLY... I have been able to make subsonic 300BO rds of 172 grains cycle. You are not bound to shooting 220 -240 gr bullets.
With a pistol length gas system you also do not need to alter your buffer spring... Remember, the object of Blackout is to turn one gun into two so you don't want to do anything to affect 556 performance just so you can shoot Blackout out of an upper with an incorrect gas system....bottom line- pistol length rules!

 

[babalou]

Tomkat

"1:8 Twist with Pistol Gas System (for better cycling of subsonic ammunition)"

http://www.shop.tomkatammo.com/product.sc?productId=64&categoryId=13

TomKat Ammo, They specialize in 300 BO and Subsonics.

I was just there late last week. The nice gentleman in the front said he prefers and recommends pistol length, especially for subsonic. I got 200 rounds of 300AAC both 110 and 150. Also got some new subsonic to try. He also showed me a kick butt short 300 upper with a side charger. Damn guess I will be visiting soon enough

 

[freebird]

Pistol length it is, for sure.

Yea, I saw that side-charge upper also, it is sweet!

 

[freebird]

At TomkatAmmo/TKDefense our experience has led us to use the pistol length gas system and HBAR barrels exclusively. This combo can take anything that you can throw at it and trust me, our 110 gr Vmax 300AAC at well over 2400fps are pushing the guns limits. Our 208gr subsonic ELD and AMAX bullets cycle flawlessly but MORE IMPORTANTLY... I have been able to make subsonic 300BO rds of 172 grains cycle. You are not bound to shooting 220 -240 gr bullets.
With a pistol length gas system you also do not need to alter your buffer spring... Remember, the object of Blackout is to turn one gun into two so you don't want to do anything to affect 556 performance just so you can shoot Blackout out of an upper with an incorrect gas system....bottom line- pistol length rules!

Great help, thanks!
Do you use HBAR exclusively due to your interpretation of MD law, or some other reason?