M4 Vs M16?

studman5578

New member
Is there a dfference? They look the same, same caliber, the M4 was developed in like the late 90's but the M16 is from the 60's (according to wikipedia). is there a difference with the parts or somethingl like that?
 
Colt wanted to develop a shorter version of the M16 that was still reliable and they pretty much determined (at the time) that the 14.5" barrel of the M4 was the shortest they could go without sacrificing a lot of reliability. There were short versions developed in the 60's (like the XM177), but they weren't M4's.

They share a lot of parts, and they are built from the same basic platform though. The M16 itself (meaning the 20" US military AR15 basically) has endured plenty of changes over the years as well.

Here you can see an M4 with an M16A2 in the background. The newest M16's are M16A4's (and some M16A3's in the USN), which come with a flat top upper and a KAC rail.

M4carbineandM16A2inbackground.jpg
 

Hkmp5sd

New member
One of the major differences is the original M16/M16A1 was a select fire weapon capable of full auto fire. The (most) M4s are select fire, but the full auto feature has been replaced with a 3-round burst system. This was a cost saving change. Instead of spending many dollars to buy lots of ammunition to teach soldiers proper trigger control, the government opted for a mechanical device inside the gun that limits their fire.
 

Quentin2

New member
The M16A3 is not a flat top like the M16A4. It's basically the older M16A2 but selectable to full auto instead of 3-round burst.
 

Skyyr

New member
This was a cost saving change.
Because everyone knows how the Government is concerned with saving money...

He's correct, though. The GI's were burning through too much ammunition, costing too much money and wasting too many supplies. The original M16's were full auto, whereas the A2 and A4 went to 3-round burst to conserve ammo and prolong weapon life. The A3 is full-auto only because of Navy requirements.
 

studman5578

New member
so to summarize:

M16 came before the M4.

The changes were that were made:
M16 M4
20" barrel 14.5" barrel
auto fire burst fire
solid carry handle removable carry handle
solid stock telescoping stock

does that about cover it?
 
Not exactly.

M16 came first.

M4, M4A1 = adjustable stocks

M16, M16A1, M16A2, M16A3, M16A4 = Fixed stocks.

M16, M16A1, M16A3, M4A1 = full auto.

M16A2, M16A4, M4 = 3 round burst.

M16, M16A1, M16A2, M16A3 = fixed carry handles.

M4, M16A4 = flat tops.

Anything else you wanted to know?
 

orangello

New member
Why did they change it from a 1/20 twist to 1/7 twist? Was it because of the rate of fire changing? (AR ignoramus here)
 

Quentin2

New member
I wasn't meaning to say that the M16A3 was the same as the M16A4, just that they are newer variants of the original M16. Thanks for the clarification though, I see how the way I worded that could be misunderstood.

I wrote an article on M16/AR15 history here.

http://www.ar15pro.net/2008/08/in-be...5-history.html
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Excellent articles you have on your blog, RockyMtnTactical! I'll have to read more, thanks for the links.

I only commented earlier because there's so much misinformation concerning the rare M16A3 on the Internet. And since so many commercial AR-15 flat tops are erroneously referred to as "A3" instead of "A4" it's easy to see why.

Just wanted to clear it up here that the M16A3 was introduced along with the M16A2, not the M16A4.
 
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