Ar Gas System Lengths

0

0317hopeful

Private
Minuteman
Sep 4, 2008
19
0
32
Iowa
#1
im going to get an AR when funds approve, and i want to make the most informed decision possible,
my question is about the differences in gas system length. like carbine mid and rifle
is one more reliable, durable, etc?
thanks in advance
 
#3
Re: Ar Gas System Lengths

Most reliable would be rifle length. The shorter you go, the more accelerated the wear and tear on critical parts. Eventhough Carbine systems are not UNreliable, they tend to wear parts faster due to increased pressures. There are ways you can alleviate this with some simple upgrades. It should depend on what you plan to use the weapon for. If you want a really short barrel, you'll have to use carbine length, but in general if the length permits a mid length is more desireable for the above reasons.
 
#4
Re: Ar Gas System Lengths

its for a 16'' barrel. im looking at the rock river A4 midlength, i like the midlength for the looks over the carbine length, so the above info is good knowing im not just getting it for looks,

any opinions on rock river rifles? im planning on using it as a rifle to hunt with maybe but more as a SHTF type rifle so it will be a target rifle, kinda run and gun target shooting if that makes sense
 
#7
Re: Ar Gas System Lengths

For a 16" Barrel: Midlength.
For an 18" Barrel: Intermediate Length.
For a 20" Barrel: Rifle Length.

The Chrome lined barrel wil pretty much last approximately 20K rounds and is less maintenence, while the Chrome Moly is generally slightly more accurate. If you get the Chrome-Lined, you may also want to get the lightweight version to reduce the weight, unless you just plan on shooting from the bench.
 
#8
Re: Ar Gas System Lengths

YHM was very good at communicating back and forth with me about ordering one. Look into them. Full spec design and fairly reasonable prices. Website says sold out, but you can order from the company, get on a list, and won't be charged until they have it to ship.
Chad
 
#9
Re: Ar Gas System Lengths

Given your intended all-around uses for the rifle, have you considered going with an 18" barrel with a rifle length gas system?

A little extra barrel length for a touch more velocity with hunting loads, the reliability of the rifle length gas system, and slightly better handling characteristics than the 20" barrel.
 
#10
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sickeness</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 0317hopeful</div><div class="ubbcode-body">its for a 16'' barrel. im looking at the rock river A4 midlength, i like the midlength for the looks over the carbine length, so the above info is good knowing im not just getting it for looks,

any opinions on rock river rifles? im planning on using it as a rifle to hunt with maybe but more as a SHTF type rifle so it will be a target rifle, kinda run and gun target shooting if that makes sense </div></div>

I would avoid rock river, most of their midlengths are heavy barrel (bad) and their barrels are not made with proper barrel steel. Not to mention the fact that their bolt carrier groups are improperly staked.

My suggestion to you if looking for a mid-length is to get either a Sabre Defence or a Bravo Company upper (when they are in stock). Both setups are made with top shelf components, 4150CMV chrome lined barrels and are made with full military specification and QC. The Sabre will be around the same price as Rockriver and the BCM will be about $100 cheaper.

If this is gonna be your first AR I would make sure to get a quality one. </div></div>

All my RRA carriers have been properly staked. A bit lighter than what I'd prefer but properly staked nonetheless.

I don't know why the barrel steel type really matters. The one RRA barrel I have isn't chromelined and it's quite accurate. (Under an inch at 100yds with some old Blackhills blue box 40gr, before they used vmax.)

Still I agree, RRA barrels are heavy. They use a heavy contour on pretty much all their barrels.

BCM makes good stuff.(I've used some of their parts.) I've heard that Sabre is supposed to be good stuff as well. (Too overpriced for me to try them.) This is the main reason I pick and choose each component from different manufacturers in order to do a build. So far, my absolute favorite Bolt Carrier has been the LMT enhanced. Just the carrier mind you. It really keeps the action clean and also seems to have a softer recoil with less muzzle flip. I've used RRA bolts mainly and most of their small parts. (Cam Pins, Firing pin, Lower parts kits.) Vltor makes a really nice Carbine buffer tube. My barrel choices vary from build to build. CLE, WOA, CMMG, Colt. I really like RRA's uppers, but now I've tried BCM's upper, and it's just as good.

Still if the guy is looking at getting a full factory rifle, I really think that RRA is the best value. Mine runs and shoots great. I've had no failures to date with it.
 
#11
Re: Ar Gas System Lengths

Get one built to your specifications and needs. RRA, DPMS, Colt, etc...... are factory assembly line type built guns. Why doesn't anyone use a factory bolt gun, they get a custom built one from KMW, GAP, etc...)

They get a bolt gun custom built for the extra accuracy, and the specifications they want. So why not get an AR built for the same reasons.

Just my .02 cents.............
 
#12
Re: Ar Gas System Lengths

The staking on an RRA bolt carrier is far from "proper", it is too light to displace the proper amount of metal to prevent the keys from turning. There are many firsthand account from credible sources of RRA gas keys unscrewing themselves in high round count situations such as carbine courses.

RRA guns are accurate because they are cut with .223 chambers, not 5.56 chambers which are proper for an AR type rifle. I would not shoot 5.56 spec ammo regularly in a RRA rifle. Any serious AR imo should be chromelined with a 5.56 chamber. Barrel steel relates to the lifespan of your barrel so it is in your best interest to have a milspec quality barrel.

Stick with BCM or Sabre, if you start with a RRA you will want to upgrade in the future anyways.
 
#13
Re: Ar Gas System Lengths

Do you know what mil-spec equals= lowest bidder

Chromed lined barrel is BS for 90% of the shooters out there, military uses chroned lined barrels because of the use of full auto. Its to enhance the life, nothing else.

I'm not too sure that RRA cuts their chambers to .223. But I'm not 100% sure just yet. But a 5.56 chamber is not the proper chamber, unless you want to shoot whatever ammo you can get your hands on. I use Wylde chambers and will beat any other factory guns accuracy out of the box, not to mention the overall fit/finish and feel.
 
#14
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">Do you know what mil-spec equals= lowest bidder
</div></div>

The above statement is misleading.

Correction:
Lowest bidder that can meet the <span style="font-weight: bold">minimum requirements.</span>
Military contracts are in general very profitable, which is why when the military solicits a bid for a contract, every goddamn company out there submits for it.

If RRA, Bushmaster, DPMS etc were capable of meeting the minimum quality and quantity requirements set forth by the contract, you bet your sweet ass they would be trying to get contracts.

If it were simply just a matter of lowest <span style="font-weight: bold">cost</span> you would see investment cast Vulcan crap in the hands of our troops.
 
#15
Re: Ar Gas System Lengths

RRA uses a Wylde chamber. It works fine with 5.56. To this date, I don't think there is a single manufacturer of an AR-15 that uses a purely .223 chamber. They're all rated to work with 5.56. Most are some variation that is between 5.56 and .223 in order to achieve the optimum balance of accuracy and reliability, as well as being able to safely shoot 5.56 and .223. I'm sure they're all pretty darn close to the Wylde chamber.

If someone has a boner for "Milspec" just buy a Colt LE6920. Otherwise, buy something that suits your needs. Chromed barrels suck for accuracy, and since most of us aren't shooting full auto, the erosion prevention they offer isn't really that big of a deal. Barrel life on a chromemoly barrel(Even if it's not "milspec") is going to be plenty for the average shooter.

Don't try and mislead someone because you have a hard on for "milspec". They guy wants both a target rifle and a reliable SHTF rifle. RRA will provide both. If staking is an issue, it tends to come up in the first couple k of rounds fired. I'd say that any firearm that I'd rely on would need to have that many rounds on it, before I'd bet my life on it.

For what it's worth, I've seen poor stake jobs that have failed on just about every manufacture's AR besides colt. If someone wants to get it staked properly, then they can buy a MOACKS.

http://www.m-guns.com/tools.php
 
#16
Re: Ar Gas System Lengths

Sickness, all of my AA's have pinned gas blocks and properly stacked carrier keys, so I agree with you on the importance of it. But I've bought AR's that didn't have those things done and I just sent it out to get done, which costs very little. You can easily stake you own carrier. Shit, I even have my own 556 Reamer that I check my chamber. RRA uses the Wylie Chamber on their SS barrels and the 556 on their other barrels. There are a lot of barrels out there from several companies that have excess chrome in their chambers and that is the issue and why I got the 556 Reamer. I shot some Hornady 556 75 GR TAP from my Wylie chamber and had no problem. I just think you are a little bit over the top with the "I won't buy an RRA because they don't properly stake their carriers properlly".

Respectfully,
Paul Santos.
 
#17
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">Do you know what mil-spec equals= lowest bidder

Chromed lined barrel is BS for 90% of the shooters out there, military uses chroned lined barrels because of the use of full auto. Its to enhance the life, nothing else.

I'm not too sure that RRA cuts their chambers to .223. But I'm not 100% sure just yet. But a 5.56 chamber is not the proper chamber, unless you want to shoot whatever ammo you can get your hands on. I use Wylde chambers and will beat any other factory guns accuracy out of the box, not to mention the overall fit/finish and feel.
</div></div>

Mike,
Sure it means "lowest bidder". But in our world, it means that the parts will fit!!! I'd rather have pieces that work together instead of looking for that one part that is "sold out" just because I bought a certain lower, etc. Seems more of a commonality to me than a cheap sell out.

Oh and custom is custom, I'll get whatever my smith tells me to get and wait from there.
 
#18
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body">
If someone has a boner for "Milspec" just buy a Colt LE6920. Otherwise, buy something that suits your needs. Chromed barrels suck for accuracy, and since most of us aren't shooting full auto, the erosion prevention they offer isn't really that big of a deal. Barrel life on a chromemoly barrel(Even if it's not "milspec") is going to be plenty for the average shooter.
</div></div>

I was not aware that RRAs were all Wylde chamber, thank you for informing me so I will not make that mistake in the future.

Chromed barrels do not suck for accuracy. If this is the case, can you dispute the accuracy of a Sako TRG or FN SPR, both of which are chrome-lined tackdrivers? Even assuming that a non-chromed barrel is more accurate, I doubt that 99% of the population can outshoot their AR type rifle with a iron sights or a non magnified or low powered optic. I pose the question to you then, what advantage does a similarly configured RRA have over a 6920? With prices on the Colt now as low as $1199 I see no reason to go with a RRA.

A chrome barrel is an absolute necessity on an AR15 for the purposes of reliability, ease of extraction and to prevent throat and gas port erosion. An AR is not a bolt gun: the DI system is known for causing accelerated gas port erosion due to the lack of venting at the gas block.

Understand that I am not touting the values of milspec just for the hell of it. The OP stated he was looking for a SHTF gun, if that is one of your primary purposes for owning the weapon reliability would be of the highest importance. In this case, you would want a weapon that is as close as possible to milspec.
 
#19
Re: Ar Gas System Lengths

Re: Paul Santos

Paul,
I genuinely appreciate your insight and comments. My issue is the idea that, if RRA is cutting corners on something as simple as staking their bolt carrier, where else do you think they may be cutting corners?

I have no problem with RRA, but I feel that with the price difference between RRA, Sabre and BCM, I don't see any reason why you shouldn't get the one with the best features.
 
#20
Re: Ar Gas System Lengths

I see your point about ultimate reliability. But from the beginning you never mentioned Colt. Still I have a lot of AR's that don't have chromelined barrels, and they work fine.

I really don't know how Sako and FN pulled off chromelining and accuracy. It's not par for the course. It's quite the opposite. Chromelining is known for being non uniform in thickness and effecting accuracy. If pulling off super accurate chromelined barrels, was the norm, We'd see these ELR guys chrome lining their bores on their Chetacs. Instead they're messing with coatings that sacrifice hardness and erosion resistance for an even coating that doesn't effectively change the bore and chamber dimensions. (Talk to Bobby about how he's been messing around with TiN.) And from what I hear about the FN's they can be hit or miss.

Besides not all milspec AR based rifles have a chromelined bore. Take the Mk12 for example.

I do have to agree, the Colt LE6920 is a great deal. It's the rifle that Colt should have released to the public ages ago. Instead of all that largepin/halfmoon/searblock BS.
 
#21
Re: Ar Gas System Lengths

I'm glad we can agree to disagree and keep it civil, which most places they can not.

I've worked on AR-15's for over 10 years and I disagree with your statement about chrome lining a barrel, which you say is a "absolute necessity for reliability, ease of extraction and to prevent throat/gas port erosion." I would agree again if we were talking about shooting the gun in full auto all the time, but 99.9% of the people do not own a full auto and fire maybe 1000rds a year through their gun(if that).

The comment about ease of extraction, I find in my experience untrue with properly chambered rifles and properly maintained rifles. Chrome lining does make it easier to clean, but as you stated, inherently less accurate.(to what degree differs on all guns)

I do like your comment on steel: "Barrel steel relates to the lifespan of your barrel" I would add, the quality of the steel, will dictate accuracy if chambered properly.
 
#22
Re: Ar Gas System Lengths

Scott,
I guess where I am coming from (mil/leo) I see reliability as being of primary importance for an AR15. I can definitely see your point though about not needing all the extra precautions if you are shooting less than 1k a year or so. So I guess we are both right depending on what we envision the use of the gun to be.

I personally prefer loose sloppy 5.56 chambers since I would use my carbine in a sub 300m role. I know for sure that I myself cannot outshoot it with an ACOG on top.
 
#23
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sickeness</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">Do you know what mil-spec equals= lowest bidder
</div></div>

The above statement is misleading.

Correction:
Lowest bidder that can meet the <span style="font-weight: bold">minimum requirements.</span>

<span style="color: #3366FF">If it were simply just a matter of lowest <span style="font-weight: bold">cost</span> you would see investment cast Vulcan crap in the hands of our troops.</span> </div></div>

If Hesse/Vulcan could handle the volume and support package with their Harbor Freight drill press and Dremels you would see them in the hands of our troops.
 
#24
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sickeness</div><div class="ubbcode-body">Re: Paul Santos

Paul,
I genuinely appreciate your insight and comments. My issue is the idea that, if RRA is cutting corners on something as simple as staking their bolt carrier, where else do you think they may be cutting corners?

I have no problem with RRA, but I feel that with the price difference between RRA, Sabre and BCM, I don't see any reason why you shouldn't get the one with the best features. </div></div>

We just have to consider the times we are in right now. It is very hard to get parts, and getting quality uppers is just as hard. I'd rather get a decent quality AR like a Bushmaster, RRA, ETC and fix some of the shortcomings than not have an AR at all. Even when I recently got my LMT, the first thing I did was I dropped the 556 Reamer in there and made sure it was good. I honestly think most of the major companies all put out decent products.

Chrome lined barrels, when done right are very accurate barrels. Sure, they aren't quite as good as the SS match barrels, but with the right set up 10 Rounds around 1.5MOA is possible.
 
#25
Re: Ar Gas System Lengths

thanks for all the help fellas, i doubt i will be able to rattle any gas keys loose with the amount of shooting ill be doing. Not that i wont put a fair amount through it, plus the key seems like a pretty easy fix. the DEA uses rock river rifles, so im guessing itll do the job for me
 
#27
Re: Ar Gas System Lengths

Noveske uses mid-length gas tubes. Afghan 14.5" barrel I own has one.

"My smith says", means nothing, unless your smith is Scott Medisha or John Holliger; two guys who've forgotten more than others ever knew.

If you want accuracy, you go stainless or chrome-Moly. No worries about gas enlarging the vent hole. Chrome-lined barrels have to be made over-size to allow for the chrome plating. Pretty damn hard to achieve perfection when initially rifling the barrel, much less after it's been chambered and plating has to bring the dimensions into spec. How many .0001" or hundred thousandths thick is the plating going to actually be?

If you want an AR-15 (or upper) that is "reliable and durable"; build it yourself. Then you know the components, torque values, know how to maintain your rifle and tweak and repair it.

I am very partial to 20" Service Rifle contour barrels with fast twist to handle heavy bullets for precision shooting. If you want a blaster, something to run & gun with; unless you are a member of some tatical strike team, I suspect you are romancing the concept too much. Each to their own...

For value, in a Precision AR-15 upper; it would be hard to beat a White Oak Armament A4 upper with Badger Ord handguard. Add a set of WOA detachable match sights and you would have it all.
 
#33
Re: Ar Gas System Lengths

my fave is a 16"carbine barrel and gas system beneath a full length rifle float tube so that just a bit of muzzle peeks out. front sight is mounted to end of float tube using bit of rail providing the enhanced sight radius of a rifle, the compactness and utility of a carbine and improved precision from free floating barrel and gas tube assembly. my 2 pennies anyway.
 
#34
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rookie7</div><div class="ubbcode-body">Does anyone have pictures of an ar running a rifle length gas system but with a 16" barrel?

How would it look?

thanks </div></div>

Bushmaster dissipator http://www.bushmaster.com/catalog_xm15_BCWA3S16D.asp] http://www.bushmaster.com/catalog_xm15_BCWA3S16D.asp[/url]

BCWA3S%2016D.jpg
 
#36
Re: Ar Gas System Lengths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">Do you know what mil-spec equals= lowest bidder

Chromed lined barrel is BS for 90% of the shooters out there, military uses chroned lined barrels because of the use of full auto. Its to enhance the life, nothing else.

I'm not too sure that RRA cuts their chambers to .223. But I'm not 100% sure just yet. But a 5.56 chamber is not the proper chamber, unless you want to shoot whatever ammo you can get your hands on. I use Wylde chambers and will beat any other factory guns accuracy out of the box, not to mention the overall fit/finish and feel.
</div></div>

More like the lowest bidder that can still meet the minimum requirements, which RRA would not. Their rifles wouldn't even be considered because of all their shortcomings in regards to the TDP for the M4/M16. Chrome lined barrels aren't just for full auto. They SIGNIFICANTLY enhance the service life of the barrel as well as make the bore damn near corrosion proof and are much easier to clean. Who wouldn't want that in a barrel? Chrome lined or stainless is all I'd ever want to see in an AR (or any rifle for that matter). 5.56 IS the proper chamber for an AR. It will safely chamber and fire all of the hotter NATO spec stuff out there and be reliable with the widest range of ammo. Owning an AR with a .223 chamber is kind of pointless, the Wylde chamber is generally GTG though but is not the end all be all for accuracy. Noveske definitely puts out some of, if not the most accurate out of the box ARs with their propriety chambers. That being said, lots of guys are out there shooting sub-MOA with plain old 5.56 chambers. It isn't like 5.56 chambers are designed to have an ultra sloppy fit to chamber everything like some people think. Also, fit and finish is one of the dumbest ways to grade a fighting weapon, it is about dead last in my book after reliability, durability, accuracy, etc. A 4150 CMV barrel with chrome lined 5.56 chamber and bore is the way to go in the reliability and durability department and no, those things WILL NOT make the gun inaccurate. Noveske makes chrome lined barrels with the same amount of chrome lining as an M249, nearly double that of the M4 and they still shoot incredibly well. FN SPRs are known to be accurate out of the box rifles and all sport chrome lined barrels as well.
 
#37
Re: Ar Gas System Lengths

<span style="font-weight: bold">Lewis Machine & Tool</span>

Ok, that is a guarenteed excellent engineered and precision built AR-15. I've shot and/or owned Armalites, Bushmasters, Colts, DSA Arms, Olympic Arms, POF, Rock River and Superior Arms AR-15's.


<span style="font-weight: bold">I'd trade them all for a Lewis Machine & Tool AR-15 with the Enhanced Bolt and Bolt Carrier system! It really is <span style="font-style: italic">that</span> good! </span>

I would save my coin up and dump it all on the LMT: CQB MRP Defender Model Piston 16! Yes, an LMT <span style="font-weight: bold"><span style="font-style: italic">PISTON</span></span> AR-15!

Yep, that's $2k of coin, but the rifle will last you a lifetime.

Good luck any way you decide to go.
 
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