16" A2 vs. M4

GUNN

GUNN

CGN Regular
EE Expired
Rating - 100%
21   0   0
Just curious as to what the differences are between my 16" heavy barrel, Armalite M15A2 LEO tactical carbine, and the standard M4. I'm thinking of getting a flat-top upper, but wanted to know what I would have to do to change my gun to an M4. Is it something in the lower? Strictly upper? Got me. :roll:

...where is the best place to find the parts to make this transformation? TSE, EE, Wolverine, RRA...?
 
The only difference from your rifle and a M-4 is that the M-4 has a government profile on the barrel(under the handguards). It also has a notch cut into the barrel in front of the sight so you could mount a M-203. The barrel lenght is 14.5" instead of 16". To make a M-4 you would just have to buy a new upper.
 
Many (most?) civilian M4geries have 16" barrels because in the USA where alot of these are made the barrel must be 16" to avoid paying a large "short barelled rifle tax". An m4 barrel has deeper cut feed ramps to mate with the legendary (and mostly useless on a semi AR) M4 feed ramps in a carbine upper. The barrel has a Pencile profile under the handguards to save weight and an HBAR profile from the handguard retainer to the muzzle with a small annular cutout in front of the front sight block for mounting the M203 launcher.

16" barrels are really an intermediate length and some versions are made with intermediate 9" handguards instead of the 7" M4 handguards. I think the M15A2 16" is a 9" handguard intermadiate carbine.

Here in Canada we can own 14.5" M4 profile barrels if we want to, but alot of guys (myself included) just use the US-friendly 16" barrels on M4gery builds because they are cheaper and easier to come by with a 1 in 9 or 1 in 7 twist chrome lined configuration.

Hope that helps?
 
Like Kevin said. You could build a clone, but you can't own the real thing. A true M-4 is built by Colt according to the US military technical data package. It's a carbine version of the M-16 and is built with a 3 round burst or full auto.
 
Should also mention the real M4 is available in either A2(carry handle) or A4(flat top) configuration, so build whichever way you want to. The flat top is more versatile, but the carry handle looks classic and might be a little more rugged depending who you talk to.
 
Well doing some digging -- ALL US M4 and M4A1's are flatop.

Some of the XM-4's where A2 CH'd and the M16A2 Carbines (basically a XM-4 before the M4 tdp was finalised) issued to USSOCOM where A2 CH'd as well
 
GUNN said:
Just curious as to what the differences are between my 16" heavy barrel, Armalite M15A2 LEO tactical carbine, and the standard M4. I'm thinking of getting a flat-top upper, but wanted to know what I would have to do to change my gun to an M4. Is it something in the lower? Strictly upper? Got me. :roll:

...where is the best place to find the parts to make this transformation? TSE, EE, Wolverine, RRA...?
Click to expand...

TSE (DPMS), EE(whatever) and Wolverine(Armalite/Eagle Arms) are all viable choices. You could also pm Dangertree as he is a Stag Arms dealer.

Other options include DLASK (manufacturer), Ellwood Epps (Bushmaster and DPMS), Lever Arms (Norinco AR's) and a whole slew of other guys who slip my mind.
 
KevinB said:
Well doing some digging -- ALL US M4 and M4A1's are flatop.

Some of the XM-4's where A2 CH'd and the M16A2 Carbines (basically a XM-4 before the M4 tdp was finalised) issued to USSOCOM where A2 CH'd as well
Click to expand...

Interesting, but building a clone of either is very possible on the civilian market. AR's - the lego of the gun world!
 
If you go the 16" barrel length route, get it as a mid-length gas system with mid-length handguards, I find the 16" with short handguards a little funky to me and the mid-length gas system will give you a better performance. 8)

The M4 style feedramp cuts can be had for any length of barrel, but these cuts extend into the upper receiver, so you need an upper style that matches your barrel.
 
furet said:
If you go the 16" barrel length route, get it as a mid-length gas system with mid-length handguards, I find the 16" with short handguards a little funky to me and the mid-length gas system will give you a better performance. 8)

The M4 style feedramp cuts can be had for any length of barrel, but these cuts extend into the upper receiver, so you need an upper style that matches your barrel.
Click to expand...

That's simply wrong. A properly constructed M4 length carbine will function every bit as well as a 16" intermediate. Looks is a personal matter, but you;re not correct about function.

If it was in issue, US armed forces wouldn't issue it. LOTS of people make 11.5" or even 4" barrels work reliably, though the lower you go, the more you might benefit from using M16 bolt carriers...
 
Actually Furet is correct.

Armalite and 5SFG (ABN) S7 (Force Mod) cell determined the midlength was less harsh on parts than the carbine gas system, and had a greater MRBF. That is the reason that the 6.8 carbines are midlength.
 
Uh.. ok, so what is MRBF and what is a 6.8 carbine? And if that is true, why is Colt still making the M4 carbine at 14.5" with the 7" carbine gas system?

FWIW, I've not seen an M4gery "wear out" from normal civilian use with the exception of replacement springs and gas tubes here and there as necessary.
 
Claven2 said:
furet said:
If you go the 16" barrel length route, get it as a mid-length gas system with mid-length handguards, I find the 16" with short handguards a little funky to me and the mid-length gas system will give you a better performance. 8)

The M4 style feedramp cuts can be had for any length of barrel, but these cuts extend into the upper receiver, so you need an upper style that matches your barrel.
Click to expand...

That's simply wrong. A properly constructed M4 length carbine will function every bit as well as a 16" intermediate. Looks is a personal matter, but you;re not correct about function.

If it was in issue, US armed forces wouldn't issue it. LOTS of people make 11.5" or even 4" barrels work reliably, though the lower you go, the more you might benefit from using M16 bolt carriers...
Click to expand...

Claven2, I didn't say 14.5" or shorter can't be made reliable, I simply stated that if your going to use a 16" barrel, it might as well be a mid-length, for it allows for smoother cycling and overall operation vs using the short gas system. And I still think a 16" with short handguards look weird :wink: but that is a personal choice.
 
Here is a pic of the M4 cuts, left pic is standard and right pic is Colt M4 feedramps. Notice the ramp notches extending into the upper receiver.

m4feedrampcuts0wz.jpg
 
FWIW, my A2 has standard ramps and my M4gery has M4 ramps. How much difference does it make in semi-auto mode? None. Nadda. Zilch.

Of course, if you install a standard barrel into an extended feedramp upper, THAT might cause issues as bullet tips could potentially get hung up on the "lips" of the standard barrel ramps... :shock:
 
Also the other way around can cause issues too, I had a configuration which had a barrel with extended cuts in a std upper, you could see copper fooling on the edge of the upper where the extended cuts should be, it never caused FTF's but would likely make a mess of accuracy. Best is to keep A with A and B with B.

Like Claven2 said, M4 cuts are for improved full auto operation in short gas systems and more so when using the longer 68gr rounds (I believe this was a quick fix by Colt due to reliability issues with M4's). In a semi-auto not really an issue, you go with what you can get.

GUNN, to answer your question, all our AR-15's versions use the same lower, they are all semi-auto, so any style upper will work with your AR-15. One difference does exist, some Colt versions use a "Big hole" style vs std. Adapters do exist for matching different styles.
Your other choice is really based on personal preference and matching barrel to upper with regards to the M4 feedramps.
 
You must log in or register to reply here.
Back
Top Bottom