I see the M4 designation frequently accross manufactirers, but  can't figure out just what it means, as opposed to things that are not M4.

See the Acronyms and Abbreviations thread tacked at the top of this forum as a starting point.

better yet...

world.guns.ru/assault/as17-e.htm

An M4 is a Carbine version of the M16/AR15.

Not a stupid question.  The world of AR's is a complex one.  I have had mine for over five years and I still come up with questions.

Quoted: I see the M4 designation frequently accross manufactirers, but  can't figure out just what it means, as opposed to things that are not M4.

Best. most complete online reference I have seen is: US Assault Rifles

Nobody else has details on the M231 firing port weapon and ALL the XM and commando variants and a lot of them screw up on the A3/A4 designation facts. This one has them all.

From Forest; What is an A1, A2, A3 or A4?

Thanks guys, great stuff!

Quoted: From Forest; What is an A1, A2, A3 or A4?

Follow the yellow brick road  links and you'll see.

Don't jump to conclusions, guys, he might not be referring to guns.





Explanation: M4 is a globular cluster visible in dark skies about one degree west of the bright star Antares in the constellation Scorpius. M4 is perhaps the closest globular cluster at 7000 light years, meaning that we see M4 only as it was 7000 years ago, near the dawn of recorded human history. Although containing hundreds of thousands of stars and spanning over 50 light-years, M4 is one of the smallest and sparsest globular clusters known. A particularly unusual aspect for a globular cluster is M4's central bar of stars. M4, pictured above, is one of the oldest objects for which astronomers can estimate age directly. Cluster white dwarfs appear to be at least nine billion years old - so ancient they limit the youth of our entire universe.

The M4 Western
Motorway is the
road traffic spine
for the western
suburbs of Sydney.


The route is from
Concord to the
west of Penrith,
a distance of 40km.

Molecular Modeling and Quantum Mechanical Methodology (M4)


The "Molecular Modeling and Quantum Chemical Methodology" (M4) Research Group has been constituted as an answer to a 2000 request by the University of Girona to clarify and define its structure of research.


Along with the "Quantum Molecular Engineering" Research Group, it belongs to the Institute of Computational Chemistry (IQC), one of the research centers of the University. The IQC is independent of the Department of Chemistry and the other Scientific Departments. It is located in the research facilities at the Faculty of Sciences building.


The activity of the M4 members dates back to 1991, when the University of Girona was founded. The main activity and very own lines of research have emerged in the mid-90s, thanks to an increase in research personnel at the postdoctoral level. The group is leaded by Full Professor Miquel Duran, and by Assistant Professor Miquel Solà.

On August 29, 1940, (the day after the M3 was decided to be put into production) work began on a tank that would mount a 75 mm gun in the turret.

In March 1941 the turret was designed based on the turret on the M3 Medium.1 The Armored Forces Board selected the simpliest design out of 5 options in April 1941.1 A mockup of the T6 was approved in May 1941.1

First prototype (T6) was built and sent to the Aberdeen Proving Grounds on September 1941.1 It had a cast hull and an entrance hatch on the side of the vehicle which was later removed.1 There were also 2 additional MGs in the hull.1

Production started at 1,000 per month and increased to 2,000 and was built at 11 plants. Production was able to quickly switch over from the M3 to the M4 as they both shared bottom hulls, engines, suspension, and tracks.

M4: Standardized in October 1941 and 1,000 per month, by 1942, were to be delivered.1 Built by American Locomotive Co., Baldwin Locomotive Works, Detroit Tank Arsenal (Chrysler), Pressed Steel Car Co., and Pullman Standard Car Manufacturing Co.

M4A1: Standardized in December 1941. Built by Lima Locomotive Works, Inc., Pacific Car and Foundry Co., and Pressed Steel Car Co.

M4A2: Standardized in December 1941. Built by Federal Machine and Welding Co., Fisher Tank Division, General Motors Corp., and Pullman Standard Car Manufacturing Co.

M4A3: Standardized in January 1942. Built by Ford Motor Co.

M4A4: Standardized in February 1942. Built by Detroit Tank Arsenal.

M4A5: Built by American Locomotive Co. for Canada.

M4A6: Built by the Detroit Tank Arsenal (Chrysler).

M4: full auto carbine version of the m-16

M4 Info....From Colt Defense......................

The 14.5 barrel makes it easier to get in and out of a hummer!