Why is the m4 barrel profile so popular in civilian market? [Archive]

ambluemax

01-18-11, 10:09

Just curious, is there actually a good reason the m4 barrel profile is so popular in the civilian market for ar carbines or is it just to be tacticool because the military uses them? It seems to be the default barrel for general purpose civilian M4's, but to the best of my knowledge the only reason for the profile is to mount an M203 granade launcher...since civilians don't really have that need wouldn't a medium contour full thickness barrel be a more appropriate choice for general use?

AngeredKabar

01-18-11, 10:12

Because that's the barrel profile the major AR manufacturers put on most of their rifles.

Appalachian

01-18-11, 10:28

Because that's the barrel profile the major AR manufacturers put on most of their rifles.

This ^ as a result of somewhat of a "reverse" product placement IMO. Same reason there are essentially un-usable bayonet lugs on 16" carbine gas barrels. Aside from the availability of front sight assemblies from the forging suppliers I would venture a guess it is because the Army has them. Same thing for that bass ackwards (but still functional, don't get me wrong) gov't profile "M4" bbl. As soon as something hits the supply or RFI system it generates a bit of a "oooh that is cool, I want one too" bow wave. Just my opinion. It is funny to watch some instances of this unfold though (plate carriers with no plates, those stupid flare launchers under ARs, plastic ACHs, chinese ACOGs:haha:....the list goes on). Of course the barrels arent in that category, but I believe the same philosophy applies.

Artiz

01-18-11, 12:05

Mainly because that's what's available. Carbine 14.5" and 16" barrels pretty much all have the M4 profile, because they always have been made like this, apart from lightweight profile and SS barrels, standard carbine barrels all come this way. I myself would rather not have the M203 cut on my 14.5" carbine, but that's just me, I don't care about the "coolness factor".

MistWolf

01-18-11, 12:06

BAC

01-18-11, 12:11

Because it's what the military uses, and it's what most larger manufacturers assume consumers want. Thankfully consumers are starting to push for more intelligent barrel profiles.

-B

ForTehNguyen

01-18-11, 12:33

economies are scale are already there for military production so just spit out the same stuff for civilians.

Sry0fcr

01-18-11, 12:37

Because it's what the military uses, and it's what most larger manufacturers assume consumers want.

This pretty much, except for the assume part. We're in the extreme minority of gun owners/shooters.

rob_s

01-18-11, 13:37

What BAC said. Except to add that given that our choices for years were basically HBAR vs. M4, M4 was the less stupid.

Wolf Spyder

01-18-11, 17:36

What BAC said. Except to add that given that our choices for years were basically HBAR vs. M4, M4 was the less stupid.

Less stupid. I love it.

I don't like the M203 cut on the M-4 profile barrels. Not only is it pointless for almost every civilian, I think it might adversely effect accuracy. I looked high and low for a barrel that does not have the m203 barrel cuts. All I could find at the time was a Medium Contour barrel, or what has been called a SOCOM profile barrel. The Medium Contour barrel is lighter than a Heavy Barrel, as far as weight goes. I figure it is stiffer than an A1 profile or light profile barrel and therefore more accurate. It is my guess that a stiffer barrel has less barrel wip. But that is just a guess on my part. As it turned out, I like really it.

Now, just as soon as Daniel Defense comes out with a CHF Medium Contour mid-length gas 16 inch barrel, not only replace the barrel on this carbine, I'll buy a complete DD upper for my next build.

WWhunter

01-18-11, 21:42

Opinion...opinion only...but I think it is mostly all the couch potatoe ninja's see what the GI has and thinks of himself as a harden warrior if he has a weapon like the GI.
Me...proud of my military time...carried and shot one enough to know that I have no need for the M4 profile. I have several AR rifles and the closest I have is a CAR type. all the rest have been built for a different purpose. I built my lightweight many years before it was the fasionable thing to do.
Can't really say that the M4 profile is all that is available either. There has always been different types available since back in the 70's. Heck one of the first one's I built was a 16" 6mm-.223. This was in 1980.
WW

GlockWRX

01-18-11, 23:02

Also for a while it seemed like the only 1:7 barrels that were available had an M4 profile.

An Undocumented Worker

01-18-11, 23:27

I'm waiting for Daniel Defense to start selling thier 18 middy S2W barrels assembled with a front sight base before I start putting together a new rifle. I just wish I could get em with a melonite finish vs parked and chromed.

tirod

01-19-11, 00:28

I just bought a melonite 16" midlength SOCOM profile, with matching bolt carrier. No M203 cuts. Free bolt, cam and firing pin included.

Standard stuff for ARPerformance. Step away from the Chart suppliers, you find stuff. Some other brand does, too, Noveske or something?:D

rob_s

01-19-11, 04:47

There is no such thing as "free". ;)

10mmAuto

01-19-11, 05:22

I assume a lot of it has to do with not wanting to re-tool existing production lines, Bushmaster's ACRs as far as I know to this day all feature an M4 profile barrel even though 99.9% of civilians won't be mounting one and the ACR does not require the style of mounting the cut necessitates.

Spiffums

01-19-11, 10:15

I believe it's also due to nomenclature. The average person walking into the funstore wanting an AR carbine "knows" the "M4" is the carbine and the "M16" or "AR15" is the rifle. So they ask for, and receive, an "M4"

And some sailors and soldiers too. I have a friend and his daughter and son in law came out to shoot while on leave. I pulled out the Bushmaster HBAR and they were like ZOMG YOU GOT AN M16!!

J_B

01-19-11, 13:28

Because it's what came on my 6920 when I purchased it for my patrol rifle.

I could care less if it has the M203 cut in it or not...as long as my rifle works.

iCarbine

01-19-11, 14:38

Because it's what came on my M&P when I purchased it.

I could care less if it has the M203 cut in it or not...as long as my rifle works.

My carbine was purchased for home defense/training and fun. The longest possible shot in my home is less than 20 yards and is only available at a bizarre angle. I think my plain M4 barrel will suffice for my needs and as a rookie AR shooter, I paid nothing extra for it.

Some of you may actually require something better. I imagine the M4 profile fits the needs of the vast majority of owners/shooters.

10mmAuto

01-19-11, 14:42

Some of you may actually require something better. I imagine the M4 profile fits the needs of the vast majority of owners/shooters.
I think the point is really a question about why something of no utility but with obvious although minor downsides is so common.

ST911

01-19-11, 14:44

economies are scale are already there for military production so just spit out the same stuff for civilians.

That would explain the cutout on manufacturers with defense contracts, but not for the rest, who constitute the overwhelming majority of production in the commercial market.

HeavyDuty

01-19-11, 14:50

I haven't owned or used an M4 profile in years, but back in the late 90s it was the lightest easy to find barrel profile available. I had one then that was switched out with a BM Superlight as soon as those became available in 04 or so.

We have a hell of a lot more quality options for barrels than we had even a few short years ago.

iCarbine

01-19-11, 15:02

I think the point is really a question about why something of no utility but with obvious although minor downsides is so common.

I agree with your point. I think the real question is: Why do manufactures continue to use something of no utility but with obvious, although minor, downsides? There are many things in the firearms market that leave me scratching my head.

10mmAuto

01-19-11, 15:22

I agree with your point. I think the real question is: Why do manufactures continue to use something of no utility but with obvious, although minor, downsides? There are many things in the firearms market that leave me scratching my head.
Because people keep buying them, even demanding them for no reason that people who are serious firearm users can wrap their head around. For example I doubt it would cost DPMS too much to properly stake their castle nuts or use proper buffer weights in their guns, assemble their BCGs properly etc, but people continue to buy them so DPMS does not.

Wolf Spyder

01-20-11, 10:40

Because people keep buying them, even demanding them for no reason that people who are serious firearm users can wrap their head around. For example I doubt it would cost DPMS too much to properly stake their castle nuts or use proper buffer weights in their guns, assemble their BCGs properly etc, but people continue to buy them so DPMS does not.

Ahh, yes, but the "Holy" Chart is gaining in popularity. Just the other day I was at the local "fun" store (as someone called it on this thread). When I heard a 20 something year old kid ask the Gun Guru Sales Commando behind the counter which one of the AR15's on the wall ranked the highest on the Chart? Of course the guy behind the counter said "Huh?" But the point is the average buyer is starting to notice. Seller won't be far behind.

500grains

01-20-11, 12:04

What BAC said. Except to add that given that our choices for years were basically HBAR vs. M4, M4 was the less stupid.

Hee! Hee!

It's great that there are so many non-stupid options now available.

Bushmaster-M4A3

01-24-11, 00:22

.45fmjoe

01-24-11, 14:54

A light barrel would be more handy than M4. The M4 is fine though, it's at least better than HBar. THe problem with 16" barrel is that it's the wrong profile, with too much sticking out front that bothers me more. I'd rather have a midlength.

Same with me, I swapped the 16" barrel off my 6920 for a 14.5" Colt M4 barrel because I couldn't find a 1/7 twist RO723 barrel. And of course, a month after I do this I find two used complete RO723 uppers at the gunshow for $450/ea. FML.

LRB45

01-24-11, 19:51

Ignorance on my part probably. When I bought my first upper that was what I saw the most on the web, so I purchased one also. It does its job though.

BaileyMoto

01-27-11, 08:48

In this particular platform, I think it just 'looks right'. I went with the 'proper' m4 profile on purpose. :)

NoveskeFan

01-27-11, 09:26

Because when the zombies come I'll be able to storm the local Fort or Base and attach a grenade launcher with no problem...duh:p

JimT

01-27-11, 11:42

When I purchased my first 16" M4-type uppers (Colt, LMT) back in 2003 - 2004, there weren't too many offerings. Back then it was between the following:

1) M4-profile
2) HBAR
3) HBAR/Dissipator

The M4 profile made the most sense to me at the time since it was the lightest. Since 2004 I have acquired two more M4-profiled 16" uppers, and do not regret those purchases. They still suit me just fine in the home defense/class/fun role(s). There are lighter offerings on the market now, and might look into them when it comes time for replacements or whenever I get bored and build up another stick.

Dionysusigma

01-28-11, 16:05

Artiz

01-28-11, 16:16

My question isn't exactly "why is the M4 profile still offered, but rather this:

What are the disadvantages of the M4 profile? Is it just more difficult to keep the exterior clean? Is it less accurate? :confused:

I don't think there are a lot of disadvantages, if any. Maybe if a lot of rounds are fired in a short time... but I don't think it's the M203 notch that is going to cause any issue, but rather the thinner profile under the handguards making the barrel front heavy.

HeavyDuty

01-28-11, 21:18

Every time I see those sharp cornered cuts I think "stress points".

rob_s

01-29-11, 05:17

My question isn't exactly "why is the M4 profile still offered, but rather this:

What are the disadvantages of the M4 profile? Is it just more difficult to keep the exterior clean? Is it less accurate? :confused:

For those that prefer logic and reason, it's illogical and unreasonable given the lack of M203 launchers in most of our safes.

However, the 203 cut isn't really the issue for me as I think the A2/govt. profile barrel is equally as useless. If I wanted that weight barrel I'd buy one of Noveske's N4 barrels that are designed to mimic the M4 barrel weight in a much more rational profile. If I was OK with the barrel being thin in one section, I'd buy a barrel that continued that same profile such as the various "pencil" and "lightweight" offerings available now.

So while the M4 profile isn't going to spontaneously combust, or mysteriously warp and bend under fire, it is simply not the best answer to any use that I would have for an M4, and isn't even a reasonable compromise given the options we have in today's market.

Dionysusigma

01-29-11, 16:17

So primarily cosmetics? :confused:

rob_s

01-29-11, 17:17

So primarily cosmetics? :confused:

No.

So, primarily trolling?

Quentin

01-29-11, 17:36

...
However, the 203 cut isn't really the issue for me as I think the A2/govt. profile barrel is equally as useless. If I wanted that weight barrel I'd buy one of Noveske's N4 barrels that are designed to mimic the M4 barrel weight in a much more rational profile. If I was OK with the barrel being thin in one section, I'd buy a barrel that continued that same profile such as the various "pencil" and "lightweight" offerings available now.

So while the M4 profile isn't going to spontaneously combust, or mysteriously warp and bend under fire, it is simply not the best answer to any use that I would have for an M4, and isn't even a reasonable compromise given the options we have in today's market.

Glad to hear that Rob... at one time the government profile really confused me. At first you think surely there's a reason for it, after all it was used in all those M16A2s. But you look at the thin section under the handguards and the thick diameter out front and think to yourself "that ain't right". Anyway, it's hard to break with tradition and go with a LW barrel - until you hold one.

Suwannee Tim

01-29-11, 18:16

Dionysusigma

01-29-11, 20:01

No.

So, primarily trolling?

Not my intention. I'm trying to figure out why.
So while the M4 profile isn't going to spontaneously combust, or mysteriously warp and bend under fire... Which to me, says that there's nothing outright wrong with the profile.
... it is simply not the best answer to any use that I would have for an M4...Pure opinion.
...and isn't even a reasonable compromise given the options we have in today's market.I ask again:

Does the actual M4 profile adversely affect accuracy?

Does it affect barrel life?

Is there any evidence of HeavyDuty's aforementioned "stress points," namely recorded failures of M4 profile barrels failing at those specific points?

As you also stated, the gov't profile (in general, including the M4 profile in this category of types that are skinny under the handguards, then increase in diameter underneath and forward of the FSB) are "useless" and "irrational."

Is it merely a balance issue such as Artiz put forth?

Is it an unsuccessful attempt to create a barrel that is lighter, yet not "whippy?"

Are they inherently no more or no less accurate than a lightweight profile?

Or, is it a combination of all these in that they're heavier than a lightweight/pencil profile, and are no more accurate than the lightweight/pencil profile (thus having more obvious downsides than upsides)?

I don't mean to come across as "trollish," nor annoying. This is simply something I neither know much about, nor discussed often, just that it's "bad." I just want to know, and figured asking experts and industry professionals was the best way to find out.

Quentin

01-29-11, 20:41

I'm kind of new to this AR thing, 2 years and a few days. I decide to buy a couple of them and I look at this barrel profile and scratch my head and wonder "what the hell is that step for?" Didn't take long to find out. Grenade launcher. Just what I need. Having a machine background I can tell you for certain it would take a few minutes to revise the drawing to omit the step and a few minutes to change the lathe program to omit the step. My main-most AR is an LMT piston gun. Why a piston? Because the barrel doesn't have a stupid looking step on it.

Well that's the first time I've heard that justification for a piston AR! Not disagreeing with your choice ST, you may love the piston but I'd rather just get a DI gun without the M4 notch. And it's pretty easy to do except when they're out of stock like they have been lately.

GlockWRX

01-29-11, 20:54

There is nothing inherently wrong with an M4 profile barrel, no degradation in accuracy or anything like that. It just serves no purpose. Kind of like a bayonet lug. I don't shop for rifles with 203 cut-outs, but I won't kick one to the curb just because it has one. My 6920 and DDM4 both have them. It is especially useless on the DD, but who cares? It shoots straight enough.

And I believe the reason there is the heavy profile forward of the FSB is to keep the barrel from bending during bayonet use and other military tasks. In the old (circa 1992) US Army smart books they showed diagrams of soldiers using the rifle to boost each other over walls, one holding the stock and the other holding the barrel. They also showed soldiers using them to evacuate casualties, holding the rifle in the same way with the wounded soldier sitting on it. Military rifles lead hard lives.

HeavyDuty

01-29-11, 21:59

Is there any evidence of HeavyDuty's aforementioned "stress points," namely recorded failures of M4 profile barrels failing at those specific points?

You're reading more into it than I intended. I'm sure failures at the cuts are exceedingly rare if they've ever happened at all. I'm referring more to possible internal stresses that could possibly affect expansion and contraction as the barrel heats and cools.

This is based on stuff I picked up from my tool and die maker stepfather many years ago and not on any knowledge of barrelmaking.

a1fabweld

01-30-11, 01:23

If I could have it my way, I'd be rolling a 16" mid length barrel, .750+" behind the gas block, chrome lined steel, 1/7-1/8 twist, no M203 cutout, barrel. I just don't get the limited contours offered in AR type barrels.

10mmAuto

01-30-11, 03:06

I doubt any catastrophic failure has ever occurred during normal use because of the cut. That being said you don't have to be a engineer to know its not as mechanically sound as a barrel without the cut. Its not a big deal but there it is.

Suwannee Tim

01-30-11, 07:36

Every time I see those sharp cornered cuts I think "stress points".

The proper terminology is "stress riser" and the cut is a stress riser. If it doesn't raise the stress to a level where fatigue failures occur then there is no problem in that regard, and evidently it doesn't as there are no reports of failures. It does make the barrel less stiff and that will affect accuracy though it would be hard to guess how much. You could shoot a rifle without the cut then install the cut and shoot again. Probably not much by carbine standards. It just doesn't look right.

..... I just don't get the limited contours offered in AR type barrels.

In a bolt action you can have literally any profile you want.

Suwannee Tim

01-30-11, 13:17

Well that's the first time I've heard that justification for a piston AR! Not disagreeing with your choice ST, you may love the piston but I'd rather just get a DI gun without the M4 notch. And it's pretty easy to do except when they're out of stock like they have been lately.

Seriously, that's not why I got a piston gun. I'm not that shallow. I got it because a piston is different. Cool. Much better reasons. The lack of the 203 feature was a plus.