Is it more or less official that a carbine gas, 16", m4 profile barrel is the least efficient barrel design available to the general public?

From how it reads on the internet, I am surprised any company still sells carbine length gas 16" barrels, m4 profile none the less?

I personally kinda like the look of a carbine gas 16". but it doesn't seem to be thought of too highly these days with the proliferation of middies

Anyone care to explain why they might choose such a barrel if given the option of a middy?

16" m4 VS. 16" mid from say...Bravo. Someone has to be buying m4 barrels, because even companies that sell middies still make them; so if there is anyone in the crowd supporting the m4 barrel design still chime in!  

I have the option to save 45 dollars on a 16" m4 upper compared to a 16" middy; both identical in every other way, materials, twist, so on so forth. Middy justify $45 more?

Is there even one realistic advantage to the carbine gas system on a 16" barrel?

Also has there been any head to head tests using rifles identical in every way minus their gas systems?

There is no functional difference between carbine & middy. Internet people claim that middys have a reduced recoil impulse, but in my personal experience, I think it's mostly just hype.

The pros of a middy are that if you use a fsb, you have a little bit longer sight radius. They are also less prone to being over gassed.

I own, shoot and enjoy multiple carbines and middys.

Midlength gas systems most definitely are softer shooters than carbine systems. Have you ever shot the two back to back? It's noticeable.

Really overblown unless your barrel is over 16". Midlength does have lower pressure than carbine driving back the bcg and with gas ports/barrel length being equal it is noticeable in recoil pulse to me, but not a dealbreaker either way. I like Midlength in a 16" and carbine in anything shorter. I like rifle length in 18" and up.

 

Yes, every time I'm at the range. Any difference in perceived recoil is so negligible that I'm not sure if it's even real.

haha, thanks for all the responses so far, if you guys can make a good enough case for the carbine gas that it saves me some cash my wallet will thank you!

Someone get me video of a side by side and wear monitoring please lol

I got to agree with that.  I know some folks really talk up the "soft" or "smooth" shooting mid-lengths, but I have and shoot both and I just don't feel it much if any at all.  But there are so many variables that can come into play with the perception of recoil that calling it fact or fiction is pointless.  The comment about a longer sight radius is indisputable, if using iron sights anyway.

 

in a 14.5 carbine just use a wolf x power recoil spring,LMT enhanced carrier and 9mm buffer it increases dwell time and produces a softer functioning carbine....but lets not forget the wear and tear select fire weapons go through has nothing to do with the semi auto only world most of us live in.

I agree with him. Mid length gas vs carbine...the recoil impulse feels the same. One time I can tell the difference is between carbine or mid when compared to rifle length.   Carbine length gas systems work.

The M4 barrel profile sells because people see soldiers with them on TV.  'It's what the military uses.'  The midlength is a better setup for longevity (durability) and reducing the recoil impulse, but there are other things that effect recoil impulse.  A good running AR is all about balance, and a mid-length is balanced better than any other system.

This. The crazy thing is, you end up spending more for a barrel without the cut.....

16" carbines look like ass, get a middy if set on 16".

Carbine get a 14.5 pinned

not for nothing if the military was using quick detach grenade launchers that attach to rails wed probably see un notched HBAR barrels in use

There's part of your problem.

I might choose a 16" carbine if the price is right and it has the qualities I want (good steel, CL, right twist, profile, etc.) I have 16", 14.5", 13", 10.5" and 7.5" carbines, and feel no need to dump any of them. I also have 16" and 14.5' mids.

A lot of people say they can "feel" the difference between a 16" mid and a 16" carbine, but I'm not one of them.

Have both. Can't tell a difference in recoil. Can tell difference with SR15 gas system though

You can not just compare mid to carbine,  the gas port diameter has a lot to do with it.

This.

LMT has a carbine gas 16" offering have have done it right with their gas port size.  They even offer it with a carbine buffer. If the company knows what they're doing, it is just fine.

FWIW, I have a 16" middy DDM4v5 and LMT Defender 16" carbine-length.  I shoot them back-to-back, five shots each.  There's no difference I can tell.  On my 3rd rifle, LMT, the Griffin muzzle device and Geissele SSA make it much more pleasurable to shoot than the DD with gritty 8lb trigger and DD A2 FH.  

Lastly, my go to is the LMT.  7K rounds with no failures or parts replacements.  Regular oiling, not regular cleaning.

HD - LMT
Hog Gun - 2nd LMT
Backup hog gun - DD

As for aesthetics, all have extended rails with shaved fsb's or clamp gas block.

I love them all, but this middy thing is overblown when you have a reputable company that knows what they're doing.

I can definitely tell the difference in recoil between the two. But recoil, as perceived by the user can be subjective and be different due to many reasons. I personally, do not plan on having any more carbine gas systems, but that's just me.

All a lot of if's and guesswork. How about some empirical testing and data gathering. Have someone build a series of rifles that are identical but that have one variable per batch. To wit: same stock, trigger, barrel length, handguard, etc. Build one with carbine gas, mid-length, and rifle length. Then, various gas port sizes. Then various buffer weight etc, you get the gist of the idea?


Testing procedure: All participants will be seated at a bench rest equipped range. They will be blind-folded. A range officer will position a rifle in front of the person doing the test. They will settle in to shooting position under RO supervision. Five shots will be fired. Testee will be asked to rate felt recoil etc. Repeat with each variation of rifle.

I have a crisp $100.00 bill that says less than 5% of shooters will get even 2-3 right out of the total sample. That low a percentage likely falls within the statistical range of simple random chance.
Then subject those same rifles to machine rested firing strings until a part failure occurs. Record and post data. But that likely will never happen.

So yet another GD topic goes on.......on........on.............
My question......as long as you can hit your target, or get the level of accuracy you desire, does it really matter?

NOT TRYING TO PISS ON OP's THREAD! I am curious just how a person could notice/sense the difference between two barrels that have a difference in gas tube length of approx. 1.2-1.3 inches during an event that takes milliseconds to occur. I just do not believe the human nervous system is that finely tuned.

As always, I am more than willing to read any thing that will show me the error of my ways if my hypothesis is wrong. Have at me, guys

That's a true observation on why M4 barrel profile AR's sells well. I just like shooting and owning both a carbine and middy AR.

You'd be, and you are.... wrong.

We are all victims of fashion.

Especially the less educated we are.

I remember hating midlengths.... because I loved the "standardization" of the AR15 and the mid seemed like a bastardization of the "spec".


Then, I became more educated, realized none of that shit was important, and recognized the benefits of the mid gas system in a 16" barrel.  Now, I only own midlength gas systems on 16" barrels.  (Rifle gas on 18" and longer).  I sold all my "M4gery" barrels long ago and realize it was all just a fashion statement.  I don't need to be able to connect a M203 grenade launcher, that I'll never own, to my weapon.

I prefer the looks of carbine. Barrel contour has little to do with anything unless you are talking heavy barrel.

As far as people buying because that's what soldiers use. Well yeah. Battle proven parts and all.
If you are new to the platform it would be in your best interest to buy what works. If that means buying a clone then do it.
I really don't see any negatives to being a follower when it comes to buying the AR.

Yes because I'm the only one that has that experience. I guess my rifles are freak anomalies because it is my experience using my rifles that there is no real difference in recoil impulse.

Everybody has their own configurations and observations based on those. I know how mine run.

The mistaken assumption is that the majority of ARs being sold are to people who members of, read, and post on AR15.com and/or similar firearms enthusiast forums.

I would venture to guess that to this day, 16" M4 profile, carbine gas barrels and barreled carbines, outsell, and outsell by a wide-margin all of the other profiles or configurations currently on the market combined.  

Reasons for this could/do include the "as seen on TV" factor, as well as market/industrial momentum, and the fact that for the vast majority of shooters and buyers, including those on this website, the benefits, theoretical or not, of a 16" midlength configuration are completely and totally lost.  

Why would a consumer care to spend even $25 more on a "better" midlength to reduce parts wear on a rifle that's maybe going to see 200 rounds of ammunition a year compared to a 16" M4 that "looks" like what they recognize, and whose brand name they've actually heard of?  

The 16" M4 barrel is not going to die out because it's still selling, and selling strong.  As for "should it," who cares whether or not it continues to be sold?  As long as you can still get what you want, what's it matter of the "entry level standard" for AR carbines is still a 16" M4?  

As for those who are so concerned about the "look" of the M203 clearance relief - ::shrug:: complaining about having it is, IMHO, just as superficial as insisting on it - you're both still concerned about "looks."  Not that there's anything wrong with that - but don't put on airs that you're so much smarter than the people who do have them, because neither of you are going to use an M203.  

Point of order - it's a feature - not everyone may use it - but some people will.  If it's just as easy to produce and give "everyone" the option, whether or not they're going to use it, why is that really an issue?  

Neverminding the use of the M203 - a lot of underbarrel mounted systems make use of the clearance cut, including, say, less than lethal launchers for law enforcement use - a lot of law enforcement agencies issue 16" semi-auto M4s, too.  It seems reasonable that some users may make use of the clearance relief - why bother making two different barrel profiles when it makes very little impact to simply apply the feature to all of them - despite complaints about how it might affect harmonics, stiffness, durability - it's pretty well and proven that the "weak link" in the barrel profile is the "government" profile under the handguards - not the clearance relief - and the barrel will literally catastrophically fail before it ever becomes a problem.  

Meanwhile, while people are hung up on the "idiotic M4 cut," "government profile" (a misnomer, but a common one in the marketplace) midlengths still sell to those "in the know" like hotcakes.  ::shrug:: I would vote that the government profile in general needs to die long before the M4 profile specifically.  

Call me crotchety, but it seems to me like too many people are fixated on what they need/want/like and saying "gotcha - I know more than you" than to consider that they may not necessarily be the linchpin that the entire AR marketplace hinges on, and that other users/consumers may have different priorities and needs than them.  

Anyways, crankiness-off, enjoy your Sunday.  

~Augee

Port sizing matters a lot. A 14.5 with .058 port is very soft shooting. A 16" carbine with a .063 port is hard recoiling in comparison.

Is there any documented, verifyable proof a midlength bolt will last longer than a carbine? I have seen none.

Augee I don't know if you knew this but M203s mount just fine to the original lightweight contour barrel.

If you're running an FSB, the middy gives you a longer sight radius (good), longer grip space (good), and "looks better" (subjective). If you're running a hand guard that covers the gas block it doesn't matter IMO.

I hope so. 16" m4 profile in any gas is a stupid design.

Thanks for responses guys. still trying to decide if middy is worth 45 extra bucks.

No and no.

I did.

But I'm not sure what that has to do with this discussion.

What does that have to do with whether or not the 16" M4 barrel profile is dying out?  

Or are you referring to my comment that those who complain about it are just as superficial as those who insist on it?  

Or that the clearance relief might have some application for some users?  

I don't see how the fact that the M203 or an underbarrel system that uses the M203 mounting pattern can mount on a lightweight barrel changes the fact that a) 16" M4s continue to sell, and b) some may actually make use of the features of the barrel profile.  

::shrug:: I'd be willing to bet that if a company marketed a 16" "government profile" carbine gas barrel without the M203 clearance relief, you'd have a bunch of people bitching and moaning about how the company "doesn't think civilians can be trusted with the ability to mount a grenade launcher."  Just like the people who're never going to own an RDIAS complaining about "high shelf" lowers.  Anyways, that's another digression that doesn't have a whole lot to do with what I was saying...

~Augee

A 16" 5.56 barrel is already unnecessary, IMO. Not enough gain over a 14.5" to justify, and not gonna do what an 18" can if the FPS really mattered.

It's a barrel length that exists purely due to NFA legalities. Period.

And the fact that mid gas on a 16" barrel yields the ideal dwell time, a softer recoil impulse, and less internal parts wear makes a 16" carbine next to pointless these days.

A 16" carbine is literally the only 5.56 configuration that I would need to be gifted to actually own.

Most of it is extrapolation from the documented fact that the 20" rifle gas system has a significantly longer parts and gas port life than the 14.5. Obviously there are people with experience who have a sense that the mid length lasts longer but barring a study by the government it is unlikely that anyone will conduct a proper study.

Logistics. I would think another reason for the M4 cut barrels is plan ol cost. Since it IS the same cut as the mil uses, its obviously standardized and just cheaper by now to mfgr at a grand scale. This = more profit and easier to stock compared to other barrel types. Same as the .750 FSB being used on otherwise light weight barrels.. They're cheaper to buy (and surely find in general for stocking purposes) from a mfgr's standpoint, compared to the now much less common(now being non-mil) .625 FSB.

Are you kidding?  There is more of a velocity loss per inch going from 16 to 14.5 than with any other barrel length change.  For that 1.5" of barrel you're loosing 100 fps with m193 and m855.  That equals out to 50 yards of fragmentation range!!!!

And since the 14.5" barrel has to be pinned to 16" anyway, the total overall length difference between a pinned 14.5" and a 16" is less than one inch! (An A2 flash hider is only 1.75" long and one inch of that is threaded and taken up by the barrel, so only adding .75" extra length!)

Basically nothing your body can recognize.  Such a small difference in length is negligable and only offers a psychological advantage.

Colt doesn't  make middies. But they do make the 6720 with pencil  barrel . Which is how I went and am glad I did.
But in the overall scheme of things, how many 6920s and Smith and Wesson'so does Walmart  sell a year compared to any of the companies selling middies?
I had a Spikes Middie that I liked. But I sold it during a panic for a profit. I don't think the guy that I sold it to knew or cared what a middie was.
It was slightly easier on recoil but not really enough to make a difference to me. the longer sight radius really didn't matter either because I was using an optic.

You don't have to...

THIS!

Have to agree with this...I just finished building a 7.62x39 AR, carbine length too, and after some fiddling with an adjustable gas block, it shoots smooth and with virtually the same recoil as a 5.56...and I HATE carbine length barrels, fighting the temptation to sell this one and get the middy I found, but can't justify it.

Why is that?, because the gas tube length is not the only factor involved, though the longer gas systems will be smoother with all other factors being the same, though they seldom are...gas port sizes vary, as do barrel weights, and buffer weights.

That being said, I prefer a mid-length every day, and twice on Sunday.

I use silencer adapters so the difference will always be 1.5". When shooting from my vehicle the shorter barrel doesn't hang up on the A pillar.

This is perhaps true for Colt but definitely not for most manufacturers.

It is.

I like and own both platforms
Besides the increased gas dwell time of the middy,
the longer distance of the FSB from the lower reciever
produces more torque force that negates the percieved
torque from recoil at the muzzle.

As an owner of both... Get what you like the best. There isn't a hill of beans worth of functional difference between the carbine and middy gas on a 16" barrel beyond what some manufacturers want you to believe. A properly built middy is nice, but then again... So is a properly built carbine.
 Most of what you will read in the way of opinions on this subject amounts to nothing more than people trying to justify their own purchase decisions by bashing those of the next guy. Its no different than someone telling you that your quad rail sucks because keymod is sooo much better. I have an old Winchester lever action that will still put a hole in anything I point it at, and it was built in 1924. A lot of fads have come and gone in that time, yet the thing still works.
 I like the middy that was built for my wife, and feel that it is every bit as good of a rifle as any other that I own. I won't however, be jumping in line to dump my Colt LE6920 for a middy anytime soon. Then again, I am not a hipster. I don't wear skinny jeans, live with my parents, call myself an operator, drink Starbucks, etc.
 I am a man. I wear boots and relaxed fit jeans. I drink bourbon, and cheap beer. I fish, grow food, can shoot well, and make my own decisions. To each his own, but some of you guys remind me of listening to a couple of split tails arguing about which handbag is best. Be a man. Buy what YOU like.

It is if you want it otherwise It will make no noticeable difference. Also worth considering is the abundance of cheap M4 uppers in the EE.
I saw a brand new LMT upper less BCG for $350 and a complete Colt 6920 upper for $475.

this!

and,



i cant say i notice any reduced recoil but i do like the M4 profile because the more reward gas block/FSB and cut barrel provide a somewhat better balance for me. do not fear the M4!