Ok guys. I am building a 14.5"-16" 300 Blk rifle. This will primarily be a range rifle and serve double duty dropping Oinkers and Bambi's daddy. I've read til I am blue in the face about this cartridge. Most everyone wants an 8" barreled suppressed rifle. I do as well, but that is later down the road.

I will run supers out of this rifle. (Again, I will build a suppressed 300 that shoots subs down the road). Here are my questions

Who runs a pistol length gas tube on a 16" rifle? Is it too hard on the rifle?

Would using a carbine gas setup be better in 16" setup shooting primarily supers?

Shots will probably always be less that 150 yards (150 for range and piggies, less that 50 where I hunt for deer)

I won't have to worry about using this for HD, SHTF or a truck gun.

Tag for the comments

I have a 16" running a C gas system (SOTA barrel, which is incredibly accurate for the price) and it runs supers all day long, using a standard C buffer and spring.  If you are just going to run supers out of it, that will work fine.  Mine will run subs with a suppressor attached, but not without.

Great. I won't have a suppressor just yet (funds) so I don't see much advantage to running subs out of it anyways.

I prefer pistol gas with the 300 Blackout, even with a 16" barrel.  A 16" carbine-length barrel will be kind of touchy depending on the loads you use, whereas a pistol-length barrel should be much more consistent, supersonic or subsonic.  And there's nothing that says you can't put that can you eventually get on a longer barrel, so there's nothing really lost by going with a 16" pistol-length barrel.

some carbine barrels with run subs but it depends on the loads and if you have a can on it.  the ozark 208's run my carbine with a can easily

check out the kak value line barrels if you want good value for a pistol gas 16 inch ..

I have a smith and wesson 16 inch carbine with carbine gas and it will run subs and supers with or with out my suppressor on it , but I reload and use 1680 powder for subs . If shooting super sonic is all you plan to do then a carbine gassed gun will be less harsh. I pretty well just shoot supers through the smith since I also have an 8.5 inch and a 16 inch remington 700 .

this is my smith set up for night time varmints .

I'm almost certain I will run a carbine setup. Good news is if I ever want a shorter barrel it's just a new barrel and gas tube.

What optic is that?

Not everybody wants an 8 inch barrel, I prefer a 10.5 and a 12.5. 10% more velocity isn't such a big deal but 20% more energy is more useful, especially if you're looking at deer 150 yards away.



-Stooxie

As far as gas system, anything less than 16" needs pistol, but 16 can work with either pistol or carbine. That said, it seems that the consensus is that pistol length in a 16" seems to offer the best reliability across the huge range of bullet weights for both sub and supersonic ammo offerings. While AAC does still offer 16" carbine gas guns, most others including Noveske have moved to pistol.

Twist rate... 1:7 is where the industry is heading as a whole, no matter the barrel length. I read a blurb from AAC designer (rsilvers here) over on 300BLK forums that when they SAAMI spec'd the round they listed 1:8 twist, but wished they would have put 1:7. As a matter of fact, all AAC 300blk barrels are now 1:7 twist, and they no longer offer 1:8.

If you want to run supers and subs, both suppressed and unsuppressed on a 16" barrel, you will need a pistol length gas system and gas port diameter between .086 and .067.  Source...  http://micromoa.com/300-blk-port-size-testing/

I went back and forth on barrel manufacturers.  I looked at everything (Noveske, BCM, Wilson, Rainier), but settled on the BA due to their specs, reviews, 1moa guarantee, and combined cost savings since this is my first plunge into 300blk.  Their 16" Modern Series 300 BLK barrel has 1:7 twist, pistol gas, and .076 port size (I emailed them and asked).  This puts it right in the wheelhouse for the best statistical reliability for running subs/supers both suppressed/unsuppressed.  

Thank you. This is a lot of info that was helpful. I never looked at the accuracy guarantee from
ballistic advantage. I kinda like that! I was on the fence about buying a BCM barrel but might go with the BA for cost. It seems like it is a good quality and I can get it and the gas block for a couple dollars cheaper than the BCM.

I need to get my work bench built in my man cave so I can start loading on my own.

You're quite welcome.  I've spent the last six months reading about 300 BLK and finally took the plunge during BA's black friday sale.  For clarity, the 1moa guarantee is with match ammo, but that's industry standard on accuracy guarantees across the board.  I couldn't find a whole lot of reviews or opinions on BA's 300 BLK barrels, but I read nothing but praise on their 5.56/223 wylde offerings.  I'm only about 20 minutes from their shop, so I figured I'd give one a shot and if I had issues, getting them resolved would be pretty easy.  I ordered direct, and took the $40 pinned LPGB service, which seems to be a no-brainer.  

I received the barrel last week, and initial impressions are that it looks like a quality barrel.  I have an SR15 Mod 2, Noveske Light Recce, and BCM LW middy for comparison.   My upper, lower, and KMR rail are currently getting cerekoted, so I won't have it assembled and shot until next weekend, so we'll see.

Admittedly, I wanted the Noveske barrel, but being that this is purely a hunting (hogs/deer/song dogs) and range fun gun, I opted to try the BA since it had favorable specs at half the cost.

I just did some glancing at the Noveske barrels. Well out of my price range. Please let me know how it goes with the new rifle. I'm curious to see how flat this will shoot at a 100 yards. I'm just getting started with my 300 build. I have a lower receiver and that is it so far. Just finished a dedicated 9mm build and have to get through Christmas before I buy more parts.

The BA barrels have me (yet again) leaning towards a 14.5" pinned system, 12" rail and want to put a 3-9 VXR patrol on it.

Oh the choices.

I just made the leap recently, 89.99 pistol gas 16" ar stoner barrel from Midway made the decision easy. Shot well the first time out, doing an accuracy test Friday hopefully. I'm anxious to try it out when I get out hunting for piggies. But so far my experience is pleasant so far with the 300 BLK.

Happy reading...  http://300aacblackout.com/resources/300-BLK.pdf

I would like to Thank both of you.

I have also been looking at this setup in a 14.5
Rainier/Noveske...
I read this post days ago, and have been reading the posted link, and doing my own reading,

I just placed my order.

To bad they didn't offer a pin/weld option. They could have had more of my money.

My bronco2- let me know how it turns out! I am going to end up with the BA 14.5" barrel. I love the look of the 14.5" guns wth a 13" handguard.

I think I will buy a 13" NSR rail for this build. Make it look like a poor mans Noveske Afgan clone.

TurnTwo- let me know how you like that 3-9 patrol! I didn't get funds in time to get that one in the EE. But that is the optic I'm going to put on my 300 too.

I was in the same situation.  So many options as well as opinions.  I even bounced back and forth between 7.62x39 and Blackout.  In the end the Blackout won.  Then the gas system and twist rates came into play.  There are a bunch of sub $100 barrels out there that fit the bill, but not knowing much about their performance led to more questions.  In the end I purchased a McGowan 16" SS fluted barrel with pistol length gas system.  Since it was at $100 before shipping I figured I would take a chance.  My intentions are supers and then maybe subs later on.  My only regret right now is the twist.  It was 1/8.  Guess I needed to take a dip in the pool in order to see how the water really feels.  If worse comes to worse I can always get another barrel.

Good luck and keep us posted on what you decide.

Your post also interested me. I am in the midst of deciding how to finish out my build to use my gun for the same reasons. Please let us know how the barrels worked out for you and what parts it is paired with.


Parts I have or have on the way for my build:
JP Enterprise parts:
Low mass bolt carrier group (anyone use this on a 300 blk yet? Sonic? Subsonic?)
Armageddon trigger
Adjustable low profile gas block
MKII 12" hand guard with a few rails to attach
A2 armament balios lite upper/lower
Vltor A5 stock combo kit
Mako foregrip w/rotating bipod
Ergo grip deluxe with shelf plate
Standard parts kit springs buttons catch...etc

Parts I'm debating on:
Barrels.... Hummmmm.... Suggestions that should work with low mass bolt carrier?
I prefer a 14.5" with a pin welded compensator that doubles as a suppressor attachment point. Haven't found this yet.

Also debating on the charging handle but thinking the Avalanche silver with black handles

This is the rifle I went with as well. Its has been a great option and has been a joy to own and use.

This sums up so much I have read over the past year. And was actually pretty helpful.
I've slowly been building my 8.5in Pistol gas 300blk (KAK Barrel). And because of all that I've read I'm not sure where to go. I will be running unsuppressed w/supers. Now, my plan was to run a heavier buffer (H2) to slow it down a little due to the short gas system. And/Or put on a KX5 to pressure the system and give it more gas.
Once I finish this (Muzzle, BCG and Buffer all that's left) i plan to run a few boxes from 4 or 5 manufactures to test/break-in the gun. Then load 147gr M80 pulls as my plinking ammo and develop a Barnes load for hunting/loaded mags at home.

Let me know how it turns out! I am almost finished buying parts for mine. Ended up with this:

Spikes upper
Spikes lower
14.5" barrel (pistol length) Surefire pro comp (7.62)
13.5" NSR rail
Magpul SL stock and pretty much all little parts and trigger are just mil spec stuff

Ordering a DSG BCG, gas block, gas tube and CH this weekend. Hopefully should have it running the following weekend.

We will see how it does. Might get a stiffer spring if I feel it needs it.

Pistol gas should be OK with an adjustable gas block and would ensure operation with subsonics.  Without a way to regulate the gas supersonics would be pretty rough in a 16 inch barrel, especially with a suppressor.  I wouldn't do it if I planned on supersonic only.

I really like the suppressed setup I have on an ares scr lower.  For huntng, it's more compact and easier to move throught the brush with than a normal lower.

Pistol gas is just fine WITHOUT an adjustable gas block. I have shot tens of thousands of rounds out of the blackout and never once had a problem with it being "pretty rough" when shooting supers out of my rifles with pistol gas ports. Also an adjustable gas block is NEVER needed to ensure operations with subsonics as with any reputable barrel manufacturer will make sure their port size is proper to get the gun to cycle both sub and supers.

The 300BLK was designed without ever needing an adjustable gas block. Any reputable manufacture of the 300BLK will make sure that their rifle operates perfectly with both subs and supers without any "rough" cycling and without any need for an adjustable gas block.

pistol gas.

yes carbine gas will work, my first 300 whisper was and is carbine.

but with pistol gas you have more options for reloading powders when you eventually try subs, and you will, and even with a 16 inch rifle it is plenty of fun.

I have spent plenty of time examining the relationship between gas system and buffer/spring in a couple of different setups.  In these setups, the buffer and spring need to balance the timing and impulse of the gas system to prevent "harsh" operation.  But there's a lot more to it.

People get confused about the Blackout because it's a "rifle" round.  Well...kinda.  Really it's a bottlenecked magnum pistol round - you load it with magnum pistol powders, and the case volume is really small compared to a classical rifle round but more in line with a magnum pistol round.  300 AAC Blackout is optimized for short barrels, with most commercial loadings burning all of their powder in about 8" of barrel length.  That means that, unlike a "rifle round" with a pistol gas port, the impulse of gas (the point where the gas blows into the gas tube), and the overall volume of gas, are both much less dramatic and violent than you get with 5.56 or any other classical rifle round.  If you look at where the .30 M1 Carbine's gas port is, you might be surprised - it's a lot closer to the chamber than the port on an M1 rifle, because .30 Carbine is also a magnum pistol cartridge that's used in a lightweight carbine...

In contrast, while you can be OK with a standard carbine buffer in a 14.5" 5.56mm carbine, many people think an H2 or H3 buffer is "better."  Sometimes they explain that M4s use an H2 buffer, so that should be the standard, though M4s and M4A1s are burst/auto guns which definitely plays a big role in the use of a heavier buffer.  Here, you're talking about a true rifle cartridge that takes at least 10" of barrel to burn its powder, and that generates a much higher volume of gas in that 10" of barrel.  When folks chop barrels to 10" or less and then must use a pistol gas port, they have lots of "interesting" issues, including really harsh operation, bolt bounce and accelerated parts wear.  You can't equate short barrels with 5.56mm ammunition and short barrels with 300 Blackout ammunition because they're such different kinds of rounds.

My 8" blackout upper runs just great with a standard carbine buffer and a fixed gas block.  I have finished my 16" upper, but haven't had a chance to wring it out yet, though I am certain it will be fine with its pistol gas system running supers.  The thing that gets "interesting" is the higher back pressure you get with a suppressor, and sometimes people find that heavier buffers help a lot when running suppressed.  I think this is the real source of most people's confusion, since AAC's glowing reports of how their stuff works all include that they use a heavy buffer - but those reports also lean heavily on suppressed setups.

So OP, you should be fine with a regular buffer, and I still recommend pistol gas for any Blackout barrel.

Your information seemed as the general consensus of things I've read or been told. I have a regular buffer system and ended up with a pistol gas, 14.5" barrel. Hopefully will be able to fire Sunday as long as I can get a gas block and pin/weld my muzzle device tomorrow.

That is all well and good nut does not hold up to my experience.  I probably could have wrote a couple of paragraphs to say it in a more obtuse fashion.
What I was trying to say was a pistol gas system will let you use subsonics, while the addition of an adjustable gas block will keep the weapon much cleaner and reduce recoil while running supersonic ammo, especially with a suppressor added into the mix.

I have run into this problem before.  If the gas port is oversized for optimal subsonic operation, then you will get too much gas for supersonics.  The possible results of this are gas in your face, dirty interiors, and excessive bolt carrier velocity, especially with everyone trying to run high-speed lightweight components these days, which leads to potential feeding issues. All this talk about reputable manufacturors sizing gas ports to do it all perfectly is senseless.  To get the most out the 300 and utilize the full range of loadings possible for it, an adjustable block is almost a must.  The gas port can be sized to run all ammo, sure, but no do-all solution is optimal over the full range of pressures from the variety of possible loadings possible for the 300blk.

My favorite rifle in 300 blk can run subsonic loads that will not even cycle other semi autos I own and run the fastest supersonic loads that are safe to load, both supressed and unsupressed, without a hiccup or any blowback in my face.  The inside of the rifle stays pretty clean, too.  I built it myself and the crux of it's versatility is that adjustable gas block.  Without it, i get excessive amounts of blowback with supersonics, even moreso supressed.  And then I open the gas block up all the way and run subsonic loads that won't even cycle other  ARs that I own.  I don't have to change buffers or this or that or clap my hands.  I just turn the meter a few clicks.

When I say "pretty rough" that is sort of a relative statement, as I mean the recoil and gas in your face (and the action) are much more than what it could be reduced to without sacrificing reliability with supersonic ammunition.  Doubly so with a can thrown into the mix.

Anyway, that has been my experience

I assembled my first AR in 5.56 then a few months later an identical looking 300blk.  Both 16" carbine setups.  They both work great.

Do you sell adjustable gas blocks? Because it sure sounds like you do. Because what you are saying is a complete fabrication. To say that you don't get blowback or don't get your bolt dirty because you have an adjustable gas block is ridiculous. The amount of gas that you are limiting is so small when using an adjustable gas that there is hardly any difference as you still need to get the bolt to cycle and that still requires a lot of gas pressure to do it. Let alone with the suppressor causing a lot of soot coming back down the barrel you will get blowback and you will get a dirty bolt.

Please also tell me who these people are that are running high speed lightweight components? Just about everyone that shoots the 300BLK knows that a H2 buffer with a full auto bolt tend to run the best.

All an adjustable gas block does is add complications and fail points to a simple system. All but one of my 300BLK rifles can shoot Subs suppressed, Subs unsuppressed, supers suppressed and supers unsuppressed. I can do all this without constantly adjusting my gas block to run any of them. That means I can pick up the rifle shoot any ammo out of it without having to figure out what setting my gas block is on. This alone makes the weapon with an adjustable gas block more of a range to than one that cannot be counted on in all situations.

If you want to tinker with your gun to try and get it to run 150gr subs or if you want to be able to shut your gas off completely so it won't cycle making it a little quieter then you can look into an adjustable gas block. But it you want a rifle that is capable of shooting any production ammo in any configuration without the constant need to adjust your gas flow to make sure your gun will cycle then you don't want one with an adjustable gas block.

No, I don't sell them and I don't make them.  I think you are taking my posts way out of context.  There is no reason for hostility.

I didn't say that everyone needs one, but rather that to enjoy the full range of possibilities with 300 black I have found gas regulation necessary.
Since I started trying them the rifles have stayed cleaner, especially supressed.  I will agree that you still get a dirty bolt no matter what, but I am
talking about the whole inside of the weapon. There is no constant need to adjust unless ammunition is being used that is at the extreme edge
of the operating range.  You can just set one in the sweet spot and run factory ammo all day.  Some people just happen to enjoy not haviing shit
blown back into their face.  I will admit that I am one of them.

 Lots of people are trying lightweight bcg and buffers with the blackout, I have seen threads and responses about it many times both here and in
other places (including real life situations).  I have also seen lightweight bcg cause feeding issues, due to excessive velocity.

The things I said here are not fabrications, they are what I have seen and heard with my own eyes.  A technical forum is no place to have a silly
arguement about what amounts to a personat preference.  You like to use the well trodden path, and even though I like an easy journey I also
like to take things out of the safe zone and into the wilds to see just what is possible.  That is why we disagree here.

Barrel is too long.

This thread helped me out bigtime.
I ended up with a BA 14.5" barrel with Pistol gas 1x7.
Standard non-adjustable gas block, with carbine spring and H buffer.
Iv only got 30 rds down range with Rem 220gr Subs, and no issues. Bolt lock back each time.

Bronco- good to hear. Similar setup to what I ended up with

Finished it tonight, gas block all on and the muzzle break welded on. Get to test it out tomorrow! Really excited. I'd upload pictures except Photobucket is deciding not to cooperate with me.

Edit:



Update: It shot very well. No problems at all with the pistol gas system. All I had was Barnes Vortx 110g but it shot it no problem.