Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Site Notices
9/22/2017 12:11:25 AM
Posted: 9/12/2005 8:56:24 AM EDT
I know the M4 has 3rd burst and the M4A1 has FA. Are there any other differences?
Thanks in advance.
Link Posted: 9/12/2005 10:01:27 AM EDT

Originally Posted By No1Here:
I know the M4 has 3rd burst and the M4A1 has FA. Are there any other differences?
Thanks in advance.



M4 is the RO920 safe-semi-burst

M4A1 is the RO921 safe-semi-full

The first early M4s have a fixed carry handle.

Link Posted: 9/12/2005 10:07:15 AM EDT
I thought the M4A1 was the model # 927...wich model is the 927
Link Posted: 9/12/2005 11:17:50 AM EDT
Anyone else got anything else to add?
Link Posted: 9/12/2005 11:23:59 AM EDT
The M4A1 by spec has a 4 oz heavier barrel and a slightly lighter maximum allowable trigger pull.
Link Posted: 9/12/2005 12:28:45 PM EDT

Originally Posted By Combat_Jack:
The M4A1 by spec has a 4 oz heavier barrel and a slightly lighter maximum allowable trigger pull.



No, the M4A1 and M4 use the same barrel.

The RO921HB uses the midweight barrel.

Link Posted: 9/12/2005 12:41:18 PM EDT
[Last Edit: 9/12/2005 12:42:43 PM EDT by scottryan]

Originally Posted By pun:
I thought the M4A1 was the model # 927...wich model is the 927



There are several Colt products that are rollmarked M4

However the two I listed are the only two that are offically known as M4 and M4A1 and have US Property marks on them.

For example,

The MT6400, RO977, LE6920, etc. are all rollmarked M4 in some way, but they are not USGI weapons.

The RO977 and RO979 are equivalent to the RO920 and RO921 except they do not have US property marks.
Link Posted: 9/12/2005 2:28:22 PM EDT

Originally Posted By scottryan:

Originally Posted By Combat_Jack:
The M4A1 by spec has a 4 oz heavier barrel and a slightly lighter maximum allowable trigger pull.



No, the M4A1 and M4 use the same barrel.

The RO921HB uses the midweight barrel.




I thought the M4A1 got the heavier "SOCOM" barrel in FY 2001?
Link Posted: 9/12/2005 2:35:03 PM EDT
speaking of which- someone wanted pictures of the israeli m4s that were stamped property of us govt. I have those pictures but forgot who wanted me to post em- please im me.
Link Posted: 9/12/2005 3:38:07 PM EDT

Originally Posted By scottryan:

Originally Posted By pun:
I thought the M4A1 was the model # 927...wich model is the 927



There are several Colt products that are rollmarked M4

However the two I listed are the only two that are offically known as M4 and M4A1 and have US Property marks on them.

For example,

The MT6400, RO977, LE6920, etc. are all rollmarked M4 in some way, but they are not USGI weapons.

The RO977 and RO979 are equivalent to the RO920 and RO921 except they do not have US property marks.



Not to mention the RO777 and RO779 fixed c/h models.
Got that straight from the Colt website.
Link Posted: 9/12/2005 4:14:34 PM EDT
I've never heard of any M4A1's as of late that have standard M4 barrels. It's my understanding that they switched over to the SOCOM barrel specs which required a medium profile under the handguards.

M4- Three round burst, standard profile M4 barrel.
M4A1- Full auto, medium profile M4 barrel.

The early M4A1's did have the standard M4 barrel, but I've always heard that they ditched it for the newer medium profile M4 barrel.
Link Posted: 9/12/2005 4:33:11 PM EDT

Originally Posted By olds442tyguy:
I've never heard of any M4A1's as of late that have standard M4 barrels. It's my understanding that they switched over to the SOCOM barrel specs which required a medium profile under the handguards.

M4- Three round burst, standard profile M4 barrel.
M4A1- Full auto, medium profile M4 barrel.

The early M4A1's did have the standard M4 barrel, but I've always heard that they ditched it for the newer medium profile M4 barrel.


So the "SOCOM" M4 barrel is only for the M4A1's? Why the change?
Link Posted: 9/12/2005 4:52:21 PM EDT

Originally Posted By No1Here:

Originally Posted By olds442tyguy:
I've never heard of any M4A1's as of late that have standard M4 barrels. It's my understanding that they switched over to the SOCOM barrel specs which required a medium profile under the handguards.

M4- Three round burst, standard profile M4 barrel.
M4A1- Full auto, medium profile M4 barrel.

The early M4A1's did have the standard M4 barrel, but I've always heard that they ditched it for the newer medium profile M4 barrel.


So the "SOCOM" M4 barrel is only for the M4A1's? Why the change?


The heavier barrel handles the heat from full auto better.
Link Posted: 9/12/2005 6:50:02 PM EDT
[Last Edit: 9/12/2005 6:54:11 PM EDT by scottryan]

Originally Posted By olds442tyguy:
I've never heard of any M4A1's as of late that have standard M4 barrels. It's my understanding that they switched over to the SOCOM barrel specs which required a medium profile under the handguards.

M4- Three round burst, standard profile M4 barrel.
M4A1- Full auto, medium profile M4 barrel.

The early M4A1's did have the standard M4 barrel, but I've always heard that they ditched it for the newer medium profile M4 barrel.



The midweight barrel is standard now on a M4A1. It appeared in 2001 and became standard in 2003 with the regular barrel as an option in 2003.

I should have mentioned/clarified that earlier.

That is why there is a RO921 and RO921HB.

The military doesn't distinguish between the two. They are both USGI M4A1s, but there are two Colt model numbers for them.
Link Posted: 9/12/2005 6:53:24 PM EDT
[Last Edit: 9/12/2005 6:57:59 PM EDT by scottryan]
So technically Combat_Jack was correct after 2001~2003.

I like to use the following designations so to clarifiy everthing.

M4
M4A1
M4A1HB

Even though there is no such thing as a the designation "M4A1HB" in the military.
Link Posted: 9/12/2005 7:23:31 PM EDT
[Last Edit: 9/12/2005 7:24:22 PM EDT by Luckyvbar]
M4A1
Link Posted: 9/12/2005 7:25:51 PM EDT

Originally Posted By Luckyvbar:
M4A1
img.photobucket.com/albums/v607/luckyvbar/100_0216.jpg



Now, where, oh where didja get that?
Uncle Sugar lend it to you?
Link Posted: 9/12/2005 7:29:59 PM EDT
No
My buddies demo rifle.
Link Posted: 9/12/2005 7:32:56 PM EDT
I did four mag dumps in a row from a DOE M4A1 this spring....with their ammo even!

Good times.
Link Posted: 9/12/2005 7:34:31 PM EDT
That ain't no M4!!!!



­


That's a thing of beauty!
Link Posted: 9/13/2005 7:57:05 AM EDT
Okay, so if the M4 and M4A1 now are the 920 and 921/HB, what was the M4 before? The rifles that were designated XM4 and those initially adopted as M4 were definitly not detachable carry handle guns, and were seen with both S-1-3 and S-1-F trigger groups.
Link Posted: 9/13/2005 8:19:07 AM EDT
[Last Edit: 9/13/2005 8:30:18 AM EDT by Ekie]

Originally Posted By scottryan:
The military doesn't distinguish between the two. They are both USGI M4A1s, but there are two Colt model numbers for them.



Agreed, Colt's model numbers are typically more descriptive then military nomenclature. Here is a RO921HB box label (M4A1):




Originally Posted By Thatguy96:
Okay, so if the M4 and M4A1 now are the 920 and 921/HB, what was the M4 before? The rifles that were designated XM4 and those initially adopted as M4 were definitly not detachable carry handle guns, and were seen with both S-1-3 and S-1-F trigger groups.



The first M4 contract was awarded in 1994:

www.colt.com/law/history.asp

The burst carbines were M4's, and the full auto M4A1's, same as today. There were a few (about) 2,000 delivered with fixed carry handles (flat top not standardized until 1995). Don't know the Colt's model name for the carbines they delivered in 94/95 with fixed carry handles.

In regards to carbines delivered prior to the 1994 M4 contract we debated what these were called here:

ar15.com/forums/topic.html?b=3&f=118&t=245465&page=3

Here is a picture of some M16A2 Carbines in service in Somalia:



I am inclined to refer to them as M16A2 Carbines, in that is the roll mark. The MOD pattern room has an example of one of these, just like pictured above, Tokoi refered to it as a Colt's Model 727.

ETA:

Forgot that I have a 1990's Colt's Carbine manual, I will check and see if it has model numbers listed.



Link Posted: 9/13/2005 8:38:17 AM EDT

Originally Posted By Thatguy96:
Okay, so if the M4 and M4A1 now are the 920 and 921/HB, what was the M4 before? The rifles that were designated XM4 and those initially adopted as M4 were definitly not detachable carry handle guns, and were seen with both S-1-3 and S-1-F trigger groups.



There was never any now and before. Just because you have a carbine in US mil service does not make it an M4 or M4A1.
Link Posted: 9/13/2005 8:43:10 AM EDT
[Last Edit: 9/13/2005 8:50:02 AM EDT by Thatguy96]
Well seeing as the way we're making it out to be that the M4 is the 920 and the M4A1 is the 921/921HB, there's gotta be something very akin to now and before, because the US Army FMs and TMs show M4s as fixed carry handle, and the 920 has a detachable one.

Edit- Well, going back to the TM after that it appears I was wrong, but I still thought that original XM4s were flat top guns. A generally held belief is that the original XM4/M4s were 720s or 727s. I had heard 777 as well, but it would appear that is erroneous. Colt does a good job of designating identical guns differently depending on whether they are for the US government or for export/commercial sale, and the 777 is definitly an export/commercial model.
Link Posted: 9/13/2005 8:51:46 AM EDT
I thought the M4A1's had a heavier barrel than the M4 to make up for the high heat encountered in FA fire.
Link Posted: 9/14/2005 10:31:33 AM EDT
When the Military start using the SOCOM M4 barrel? What is the weight differences between the M4 barrel and the SOCOM M4 barrel?
Link Posted: 9/14/2005 11:13:37 AM EDT

Originally Posted By Luckyvbar:
No
My buddies demo rifle.




OH? I thought you got that in a LE6920 box. By accident.


Remember?
Link Posted: 9/14/2005 12:48:16 PM EDT

Originally Posted By WILDBILL756:
When the Military start using the SOCOM M4 barrel? What is the weight differences between the M4 barrel and the SOCOM M4 barrel?



+4 ounces, IIRC
Link Posted: 9/14/2005 1:07:49 PM EDT
Is the military still using any fixed carry handle M4's? I havent seen any personally. They've all been removable.
Link Posted: 9/14/2005 1:08:33 PM EDT

Originally Posted By Hoplophile:

Originally Posted By No1Here:

Originally Posted By olds442tyguy:
I've never heard of any M4A1's as of late that have standard M4 barrels. It's my understanding that they switched over to the SOCOM barrel specs which required a medium profile under the handguards.

M4- Three round burst, standard profile M4 barrel.
M4A1- Full auto, medium profile M4 barrel.

The early M4A1's did have the standard M4 barrel, but I've always heard that they ditched it for the newer medium profile M4 barrel.


So the "SOCOM" M4 barrel is only for the M4A1's? Why the change?


The heavier barrel handles the heat from full auto better.


So I'm guessing FA is used alot among those who are issued M4A1's.
Link Posted: 9/14/2005 1:13:36 PM EDT

Originally Posted By Horik:
Is the military still using any fixed carry handle M4's? I havent seen any personally. They've all been removable.



You can see them on the news from time to time.
Link Posted: 9/20/2005 12:50:44 PM EDT

Originally Posted By Spooge5150:

Originally Posted By Luckyvbar:
No
My buddies demo rifle.




OH? I thought you got that in a LE6920 box. By accident.


Remember?



Yea.

But I think he finally came clean on that. (at ARFcom gunpoint...)
Top Top