Mid length M4 profile?

[RX-79G]

So, a real M4 has a 14.5" barrel, and the distance from muzzle to gas block is the same as an M16. A standard 16" "M4" adds 1.5" in front of the gas block, making it impossible to mount a bayonet, and it looks odd. None of us is mounting an M203, so the M4 contours are just for fun.

The 16" mid length is supposed to put the muzzle to gas block distance back to the M16/M4 distance.

So why can't I find a 16" mid length barrel that has the M4 look? Is everyone keeping it legit?

 

[Quentin]

I've never seen a 16" midlength with a M203 cutout, either. Instead of the M4 look you get the M16 look but on a carbine!

You are correct that the bayonet fits a 16" midlength.

 

[Rubber_Duck]

Because the M203 cuts on the government profile M4 barrel are stupid and serve no purpose except for strict military M4 clone builds. And by strict clones I mean an honest 14.5" + pinned and welded muzzle device, otherwise an M4 profile on a 16-inch barrel looks even stupider and you lose the function of properly mounting a bayonet while stressing your bolt further with excess dwell time versus the already overworked system of the 14.5 barrel/carbine gas system combo.

The midlength gas system is much better suited to the 16-inch barrel and likewise we all benefit by not having those idiotic grenade launcher cuts on a non-military-spec rifle like a midlength. Uncle Sam was too lazy to simply modify the M203 to fit A2 or later barrels instead of the other way around.

 

[Coal Dragger]

Even Uncle Sugar has decided the M4 profile barrel is stupid. Witness the advent of the M4A1 medium contour profile. I have one in a 16" Colt SOCOM II, albeit carbine length gas system. It is a very good shooter.

There are better profiles for an M4 or M16 than the old gov't profile. A look around at SIONICS weapon systems, Criterion Barrels, Daniel Defense, Bravo Company Machine, Faxon Firearms, Noveske, Rainier Arms, and host of other great barrel makers reveals a host of good barrel profiles for the M4.

 

[RX-79G]

The point is that the look of M4 is preferred for its look by many people, yet you can't get that look on a mid, which seems weird.

The M4A1 is different under the handguards, but looks the same up front.

 

[chicharrones]

The point is that the look of M4 is preferred for its look by many people, yet you can't get that look on a mid, which seems weird.

The M4A1 is different under the handguards, but looks the same up front.

It may just be that the FSB/gas block on a mid-length barrel would be partly on top of that M203 cut unless the cut was moved forward?

EDIT:

Link to photo - http://trainhardshootfast.com/wp-content/uploads/2012/11/20121109_115725.jpg

From this webpage - http://trainhardshootfast.com/tag/palmetto-state-armory/

 

[MachIVshooter]

The point is that the look of M4 is preferred for its look by many people, yet you can't get that look on a mid, which seems weird.

If one is building an M4 clone, one would not use a middy barrel.

Aside from clones, I struggle to recall ever hearing anyone say they liked the ridiculous cut. See:

Because the M203 cuts on the government profile M4 barrel are stupid and serve no purpose except for strict military M4 clone builds. And by strict clones I mean an honest 14.5" + pinned and welded muzzle device, otherwise an M4 profile on a 16-inch barrel looks even stupider and you lose the function of properly mounting a bayonet while stressing your bolt further with excess dwell time versus the already overworked system of the 14.5 barrel/carbine gas system combo.

Is the sentiment held by everyone I've ever spoken with who had an opinion on the matter, and mirrors my own thoughts.

I've only bought one M4 cut barrel in my life. It was a 14.5", I did pin a muzzle break, and I also reprofiled the barrel to sub pencil, eliminating the cut entirely. That was for a budget featherweight build, and I couldn't find a 14.5" for less than the $95 M4 profile piece from JSE.

 

[RX-79G]

It may just be that the FSB/gas block on a mid-length barrel would be partly on top of that M203 cut unless the cut was moved forward?

EDIT:

Link to photo - http://trainhardshootfast.com/wp-content/uploads/2012/11/20121109_115725.jpg

From this webpage - http://trainhardshootfast.com/tag/palmetto-state-armory/

That's what would happen if just moved the sight forward. I'm talking about adding the missing 1.5" under the handguard, instead of the ugly way it is usually done in front of the gas block.

 

[RX-79G]

If one is building an M4 clone, one would not use a middy barrel.

Aside from clones, I struggle to recall ever hearing anyone say they liked the ridiculous cut. See:

Quote:
Because the M203 cuts on the government profile M4 barrel are stupid and serve no purpose except for strict military M4 clone builds. And by strict clones I mean an honest 14.5" + pinned and welded muzzle device, otherwise an M4 profile on a 16-inch barrel looks even stupider and you lose the function of properly mounting a bayonet while stressing your bolt further with excess dwell time versus the already overworked system of the 14.5 barrel/carbine gas system combo.
Is the sentiment held by everyone I've ever spoken with who had an opinion on the matter, and mirrors my own thoughts.

I've only bought one M4 cut barrel in my life. It was a 14.5", I did pin a muzzle break, and I also reprofiled the barrel to sub pencil, eliminating the cut entirely. That was for a budget featherweight build, and I couldn't find a 14.5" for less than the $95 M4 profile piece from JSE.

Yet, plenty of people buy 16" M4 looking guns, completely blowing that theory.

There is no 16" barrel gun that is an "M4 reproduction". You can add the missing length to the front of the barrel, back of the barrel or by adding a long FH. I'm just asking why there are only two of those options available.

 

[Rubber_Duck]

Yet, plenty of people buy 16" M4 looking guns, completely blowing that theory.

Or, the 16-inch M4 profile barrel just happens to be the most mass-produced of all civilian ARs and therefore the most common among the masses, whether AR-savvy or not.

 

[RX-79G]

Or, the 16-inch M4 profile barrel just happens to be the most mass-produced of all civilian ARs and therefore the most common among the masses, whether AR-savvy or not.

So, you think people shopping for a rifle just buy the most common one they see? Why did it become the most common? Is it easier to machine than a straight barrel?

 

[Rubber_Duck]

So, you think people shopping for a rifle just buy the most common one they see? Why did it become the most common? Is it easier to machine than a straight barrel?

No I don't think people buy a certain type of rifle because it's common, I'm inclined to believe that the military M4 is a desirable gun and very well-known by most because of video games or movies or whatever and when people see a semi-auto 16-inch M4-style rifle they buy it because it looks cool to them. And gun manufacturers know the M4-style rifles sell well so they crank out more of them and hence more of them are on shelves at more gun shops. My very first AR was a Bushmaster with a 16-inch M4 profile barrel, before I even knew which end of the gun the bullets came out of. But in recent years I've noticed the trend is towards longer than carbine-length free-floated metal handguards (in picatinny, Keymod, or M-lok) with low-profile gas blocks. People don't want the plain-Jane M4s of the 1990s anymore.

 

[MachIVshooter]

Yet, plenty of people buy 16" M4 looking guns, completely blowing that theory.

Or, the 16-inch M4 profile barrel just happens to be the most mass-produced of all civilian ARs and therefore the most common among the masses, whether AR-savvy or not.

This. Until pretty recently, the mid length was not very common. Armalite developed it, and others slowly adopted it. Today, however, it is the more popular variation of 16" carbines, and has even found it's way onto those as short as 13.5", as well as being used on 18" guns. Today, pretty much every manufacturer but Colt offers mid lengths. Some don't even offer carbine gas systems anymore. One really only need look at Palmetto, arguably the biggest seller of ARs and AR parts out there, to see what is more popular now; They offer 51 mid length uppers, and just 13 carbine length, not all of which even have M4 profile tubes.

But 6 or 7 years ago, just about every AR on the shelf of any gun or sporting goods store was a carbine with M4 cut barrel. So it stands to reason that a lot of them were bought

 

[ny32182]

I'll throw some speculation:

1) 16" midlength with a cut moved forward would likely eliminate the ability to mount the 203. Or at best it would make for a big gap between the back of the 203 and the magwell/barrel nut area. I don't know how a 203 actually mounts, but I'd also guess there is a rear mounting point that might have to be backed up to the magwell for some reason. On a 16" carbine gas, there is just 1.5" of barrel added in front of the cut, so the cut is still technically functional if you ever did mount a 203 (or 37mm) launcher to it... it is dimensioned the same as it is on a real M4.

2) It may be that whatever manufacturing techniques are used to make military contour barrels make it a lot easier to just add 1.5" to the front instead of stretch it in the middle and then have to move the cut further out. Again, this is speculation, but the manufacturers may be figuring that if they have to completely overhaul the contour anyway by moving the gas port and extending the turned down portion under the handguards, there is no point in going to the trouble of adding the cutout, which no one uses anyway, in a completely non-functional location.

If you want to make a REAL M4 clone, you have to go SBR, there is no way around it (see Colt LE6921).

You can permanently attach a slightly elongated flash hider and be pretty close.

But once you've moved the gas port, you aren't anywhere close to an M4 clone anyway, so why bother with the cut.

 

[strambo]

Probably because a mid-length M4 profile would look less like a real M4 than the carbine version. The most accurate look (basically perfect) would be to send a 16" M4 profile to ADCO, have them cut it to 14.7" and pin on a A2 FH.

 

[Walkalong]

The M4 cut looks weird on for a barrel that will never see a bayonet. Why it is still so common is beyond me. I can't see where the M4 cut could be accurate compared to more common rifle barrel cuts either. Super thin until the gas block and then it gets heavier. Just can't be good. The cut I prefer for an AR to be carried a fair amount is the FN "lighter profile" barrel cut that PSA used to sell. Spikes does something like it now. Lighter than the A2 cut, not as flimsy as a pencil barrel.

http://www.spikestactical.com/st-cold-hammer-forged-16-midlength-barrel-556-p-830.html

The description (And the stamp on the barrel) makes me wonder if FN makes them for Spikes now.

 

[MachIVshooter]

Spikes does something like it now. Lighter than the A2 cut, not as flimsy as a pencil barrel.

PSA, BCM and a number of others also do lightweight profiles that split the difference between government and pencil.

I used a Del Ton LW 20" barrel for my A2 build:

 

[Mosin Bubba]

I was eyeballing that Delton upper just the other day, Mach. It's tough to find a lightweight 20" barrel.

How's it shoot?

 

[MachIVshooter]

I was eyeballing that Delton upper just the other day, Mach. It's tough to find a lightweight 20" barrel.

How's it shoot?

It's a Del Ton Barrel and A2 receiver, but one I assembled. AIM nitrided BCG, and whatever JSE was slinging for the other parts. Originally built with an Anderson flat top upper, but I finally put the A2 on a couple months back.

So, I really can't comment to the assembled Del Ton uppers, but this one shoots fine. I did, however, have an issue with the barrel extension pin and FSB being off by about 3° as received. I split the difference by opening up the cut in the receiver for the pin and tweaking the FSB a little by careful Dremeling of the pin holes in the barrel and slight bending of the pins themselves.

 

[kwg020]

The point is that the look of M4 is preferred for its look by many people, yet you can't get that look on a mid, which seems weird.

Not everyone thinks they look "cool". The M-4 cuts look dumb unless you have an M-203 grenade launcher mounted to it. All they do is add unneeded weight. You will never be sorry you have a mid length rifle. I suggest you go to DelTon and pick up one of their uppers in mid length with the bayonet lug and fixed front sight. I prefer the light weight barrels. You may lose some accuracy with the lighter barrels past 100 yards but not by much. DelTon's barrels are 1/9 twist. There are other makers if you want a 1/7 or 1/8 twist.

If you want the M-4 cuts get the 14.5 inch barrel and permanently attach the flash hider. Your bayonet will still work and you get "the real thing".

kwg

 

[RX-79G]

Not everyone thinks they look "cool". The M-4 cuts look dumb unless you have an M-203 grenade launcher mounted to it. All they do is add unneeded weight. You will never be sorry you have a mid length rifle. I suggest you go to DelTon and pick up one of their uppers in mid length with the bayonet lug and fixed front sight. I prefer the light weight barrels. You may lose some accuracy with the lighter barrels past 100 yards but not by much. DelTon's barrels are 1/9 twist. There are other makers if you want a 1/7 or 1/8 twist.

If you want the M-4 cuts get the 14.5 inch barrel and permanently attach the flash hider. Your bayonet will still work and you get "the real thing".

kwg

What a weird statement. Of course not everyone like M4 barrels, but lots of people do.

 

[Tirod]

And lots of people don't. Ref all those makers how offer alternate profiles. Move into another alternate cartridge system and for the most part none of those barrels bother with a M4 cut because they are commercial civilian cartridges and will never mount the M203. Its already been discussed that it's a known weak spot and the .Gov has moved to making it obsolete. Most of the new ere grenade launchers mount on the picatinny rail now, and can even be equipped with their own chassis as a stand along unit.

The M203 cut is an anachronism and fading away. That it exists at all is typical government bureaucracy in action - instead of refitting the M203, they decided to force it's constrictive mount on the subsequent models and it's been going on for generations.

Goes to only the M4 fans keeping it on the books these days. Slavish devotion to an outdated and nearly useless provision as most guns aren't mounting the M203 anyway. That is horribly common in institutional firearms fleets while in service, but it doesn't mean it's justified for you and me. It has less value than the forward assist or carry handle sights - and we've seem them come and go. M4geries are a declining niche in the AR market these days precisely because of stuff like that.

Moot point for a lot of us, we shoot 10.5" barreled pistols, too. I am speculating but I see that as a larger market these days than building another dated and anachronistic military "homage" that can't be. Take at longer look at rails these days - KAK doesn't have a lock on them just because of a contract.

 

[MachIVshooter]

Of course not everyone like M4 barrels, but lots of people do.

Start a poll. I'm betting you'll find "lots" is more like "a few". Like I said before, anyone I've ever spoken with who had an opinion on the matter felt the cut is stupid, and the current AR market for barrels, uppers and complete rifles indicates that sentiment is held by a majority. A good friend of mine who is also an SOT did AR building for a long time before moving away from it more recently to deal mostly in NFA and Cerakote; it was extremely rare for someone to request an M4 profile barrel, and most doing 16" guns wanted mid lengths with handguards 12"-15" long.