Difference between M4 and AR-15 carbine?


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Cheeseybacon
February 13, 2007, 09:20 PM
I'm given up trying to find the perfect odd-ball EBR, so I've decided to get myself a common AR-type weapon of some kind. The question I have is, what's the difference between the 16" Carbine AR-15s and the M4s? They're both really short, and as near as I can tell they look like pretty much the same gun. Wikipedia wasn't much help on this either...

What's the difference? Is one going to be more accurate/reliable/modifyable than the other for the role of plinking and pissing off politicians and such?

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universal
February 13, 2007, 09:23 PM
M4 is a military "name" for their carbine. It has a 14 inch barrel and semi-auto and three round burst. Other than that it is about the same as an AR-15 carbine which has a 16 inch barrel. The newer M4A1 has a full auto setting rather than the three round burst.

A civilian cannot buy or own an M4.

I believe that is about it.

RockyMtnTactical
February 13, 2007, 09:31 PM
An M4 is an AR15 but an AR15 isn't always an M4.

Really, M4 is just the military designation for a 14.5" barreled carbine. Specifically with a M203 notch near the front of the barrel and a collapsable stock.

Cheeseybacon
February 13, 2007, 09:33 PM
I was just curious, I'm browsing around on Bushmaster's website and they have a bunch of rifles listed as "M4 type" right alongside the 16" AR carbines and I'm having the damnest time trying to tell the difference between the two.

Example:

16" Carbine with birdcage flash suppressor
http://www.bushmaster.com/shopping/weapons/bcwa3f16.asp

16" M4 type with birdcage flash suppressor
http://www.bushmaster.com/shopping/weapons/bcwa3f16m4.asp

redneckrepairs
February 13, 2007, 09:36 PM
As i understand it: The m4 should have " m4 feedramps " that are simply cut deeper to the point they cut into the reciever its self . This is only an advantage for full auto reliablilty with heavyer bullets , virtualy no effect on semi use . Also the m4 will have an "m4 profile barrel " which means its cut in front of the sights for clamping a gernade launcher to it , and has a thin profile under the handguards to give room for same . Millitary m4s are 14" barrells and civilian " clones " are avalable with either a 14+ perminatly attached flash hider to bring the length to 16" or as a 16" barrel with a standard flashhider.
Both carbines normaly are flat top anymore .

Hope that helped you out .

Cheeseybacon
February 13, 2007, 09:42 PM
Eww. So let me get this straight, most of these M4 clones will have a 14" barrel with a flash hider to bring the total distance up to the 16" legal limit?

Why would someone want that instead of a full 16" barrel?

If seems to me like you'd be getting slightly reduced accuracy with 14" barrel versus a 16" barrel, while at the same time receiving none of the improvements in compactness that would normally come with a 14" barrel due to the permantantly attached flash hider bringing the total barrel length back up to 16". Am I missing something here? :confused:

redneckrepairs
February 13, 2007, 09:49 PM
You just cant be a proper gear whore with a 16" tube i guess lol .

I think you summed it up nicely , the 14 has some distinct advantages for LE , military , ect as far as close quarters gunhandeling goes . The true gear heads go the sbr route and get atf approval for a real 14 tube . I just explained the options as i have seen them , not that they made sense to me . For myself my ar is a full 16" with no flash hider and is a hbar profile . For me and my use i like the weight and ballance of it . I dont compete with it tho and might well put a different upper on it to use if i were going to shoot carbine matches or 3 gun .

illspirit
February 13, 2007, 09:52 PM
Unless the flash hider is permanently attached, the barrel is measured without the hider. So a 16" barrel would be more like 17.5 to 18" after screwing the hider on.

redneckrepairs
February 13, 2007, 09:55 PM
Illspirit this is true , but iirc i saw some of the m4 uppers that were a pinned A2 style fh that mesured 16 at the end of the hider . No explaining what some folks/companys do i guess . It is verry much buyer beware in the ar 15 market anymore .

Cheeseybacon
February 13, 2007, 09:56 PM
Man, I'm gonna hafta be careful about what I buy. I was just looking the inventory available for order from my local gun dealer (http://gunstore.taylorstradingpost.com/consumers/subsites/inven_product.asp?dealer_id=954429&item=BCWA3F%2D11%2E5%2F5%2E5&instock=in&manufact_combo=Bushmaster&mod_ser_combo=None&category_combo=2&model=None&g_type=Rifle&act_type=&finish_type=None&calib_combo=223&sight_class_combo=None&price_range=None&left_handed=&youth=&Offset_rec=0&num_rec=100&item_num=) and noticed that some of these M4 types have a 11.5" barrel with a permanent 5.5" flash suppressor.

Why in the world would someone do that? That just seems rediculous to me...

Mjoilner1911
February 13, 2007, 09:57 PM
Truth told, on a thin profile barrel, there isn't much loss of accuracy between the 14.5 length and the 16 length....Mine currently has the 14.5 with a YHM "Phantom" flash hider permanently attached. Still gives good accuracy out to 250.

redneckrepairs
February 13, 2007, 10:00 PM
The main differance between a 14 or even an 11 and a 16 is velocity , same can be said for 16 vs 20 . Accuracy should not suffer much if any as long as the barrel is properly crowned ect. I chose 16 for ease of getting in and out of the pickup , while still having enough velocity to " pop " prarie dogs at 300 or so . I like the weight and stability that the hb gives me tho it is no more accurate than a light profile barrel unless you are shooting enough to heat it up the hb will absorb heat better and so take more rounds to start stringing shots . I farm and ranch so my rifle is used for vermin/ predator control more than anything .

illspirit
February 13, 2007, 10:11 PM
Redneckrepairs, my best guess is companies that label 14.5-ers with pinned hiders as 16" probably just do it to not confuse customers and/or themselves with fuzzy maths. Who knows...

And Cheeseybacon, it could be that some of the people buying the 11.5 inch barrels with the ginormous hiders are hoping the NFA SBR restrictions go away one day so they can put a regular hider on. That, or, maybe they're thinking about jumping through the hoops and register it eventually.

RockyMtnTactical
February 13, 2007, 10:14 PM
Some companys make 14.7" barrels with an A2 flash hider perm attached.

Personally, I have a 14.5" with a phantom perm. attached and I love it. It's a great, short handy length, it's got one of the best, most effective flash hiders made, and it's my favorite weapon.

CDignition
February 13, 2007, 10:14 PM
If you have an NFA M16 lower, and a tax stamp for SBR, you can build an exact M4 the US military uses... it would be fun..:)

goldshlagerxx
February 13, 2007, 10:28 PM
"If you have an NFA M16 lower, and a tax stamp for SBR, you can build an exact M4 the US military uses... it would be fun.."

just need one or the other, there are no barrel length restrictions on machine guns

redneckrepairs
February 13, 2007, 10:33 PM
Personally, I have a 14.5" with a phantom perm. attached and I love it. It's a great, short handy length, it's got one of the best, most effective flash hiders made, and it's my favorite weapon.

Sounds like a neat little setup , Mine suits me as well or better for the use i put the rifle to , but that is the neat thing about the ar platform , its modular and can be dressed up to suit what you want or need . Kinda a black barbie doll for big boys lol .

Dienekes
February 13, 2007, 10:36 PM
Had a Colt CAR-15 years back. Now have a Bushmaster M4gery 16". Biggest difference between the two is that the CAR had a nice slim barrel whereas the BM has the wannabe M4 heavier profiled barrel (to launch all the M 203 grenades you don't have). Would have preferred the lighter barrel but the BM was close to what I wanted with the A1 rear sight. DPMS makes a 16" Panther with the light barrel and of course they can be swapped if it is worth the cost somehow.

Other than looking cool there is no point to short rifled barrels combined with a different looking flash hider. The 16" barrels lose some velocity compared to the 20" ones and giving away more makes no sense.

What most ARs need is not sexier flash hiders but good aftermarket triggers.

vis--vis
February 13, 2007, 10:48 PM
Can a Civillian own an M4 (semi-auto) with the SBR class III stamp?

goldshlagerxx
February 14, 2007, 12:02 AM
"Can a Civillian own an M4 (semi-auto) with the SBR class III stamp"

Yes. Buy a lower. Fill out an ATF Form 1, write out $200 check and wait for approval. Once it's approved go out and buy any upper that you'd like. It's not really a "class III" stamp, it's a NFA stamp. They're all the same for suppressors, sbr's, sbs's and mg's. Aow's are different of course.

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