AR15 vs M4 - What's the difference?

[righteousbarbarian]

I've been trying to just learn a little more about battle rifles and I've come across what seem to be two very similar rifles. What are the main differences between an AR15 and an M4?

[BUCKMARK]

The M4 is an AR-15 in the civilian world.

The M4 is a 16" barrel with the retractable stock. There are SO many versions out now, that even most "M4's" are not M4's.

In general a Standard AR15 has a fixed stock and 20" barrel. But as I said, there are hundereds of variations out there now. All of them are ARs.

As for the military's M16...

let me try to get this right the first time....lol.

The original rifle was the M16 or Ar15 with a 20" barrel.

The M16A1 was upgraded with a forward assist.

The M16A2 got a new rear sight system and a heavier 20" barrel with round forend. The M16A2 was semi/ 3 round burst instead of full auto.

The M16A3 is the same rifle as the A2 with the removable carry handle.

The M4 carbine has the 16" barrel with the adjustable stock.


Each and every damn rifle I listed has several variants and things have changed over the years. I did my best without typing for 10 hours.

Lots of good info on the net about the AR15/M16

[BUCKMARK]

Read this

http://world.guns.ru/assault/as18-e.htm

And then this

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

[SharpShooter88]

This is exactly the reason I want to build an Ar....Soo many different configurations and parts to choose from....I am like a kid in a candy store! Better get the GF to keep that credit card out of my hands!

[markheck1]

Yeah, the M4 is basically a shortened version of an M-16, it's the military only select fire version with the adjustable stock

AR-15 is a Generalization of all of the manufacturers' semi-auto civilian versions of the M-16. It's kinda like Kleenex, nobody asks for tissues, they all ask for kleenex.

Hope this muddies the water enough for ya

[Kenshin]

Mark is correct. The M4s are 14.5 inch barrel select-fire carbines that the Army uses. The M16 is a 20 inch select-fire.

Anything civilian owned is an AR-15 unless your lucky enough to have access to NFA toys.

[adsstorm]

The AR stands for armalight which eugene stoner the designer of the first CAR (carbine armalight) worked for at the time he designed it. The first rifle was actually A 7.62 nato yet the military wanted the 5.56 for what ever reason. when the military picked up the design they designated it the m16 and somewhere along the line the patten was given to colt to mass produce these rifles. Yet over the years due to the military's designators of weapons and the models sold to civilians (retrictions placed on manufacturers by law) you will find a wide variety of what is an M4 or what is an M16. You can take the receiver of a full auto (busrt cam) m16a2 change out the hammer, trigger, disconnector, selector switch, and remove the auto sear and replace them with semi only hammer, trigger, disconnector, and selector switch and technicelly have a civilian legal fire arm. Another problem is that during the assault ban rifle years, colt in particular, went to great pains to make it to where you could not change out some of the parts like changing the diameters of the take down pins so lowers and uppers could not be switched and bolt carriers were shaved and machined so that a full auto sear could not be used in a civilian bolt. That kind of thing. Barrel lenghts can also be a determining factor in what a full auto, three round burst, or semi only rifle can be designated. Yet the reality is that you can put a fixed stock on an m4 like that of an m16 or have full auto, three round busrt, or semi parts inside of the lower recierver. Yet the stamp on the outside will m16a1 or m16a2 or maybe Ar-15 LE only. believe me when I say that if you are a government entity and you have M4 rifles the receivers may say that it is an m16a2. Which are parts that have been recycled through the system and the parts where a diffrent rifle in a past life.

[okieco]

Don't forget the CAR15. My first AR which I purchased back in 80' something was a CAR15. It was an AR15 with an 11.5" heavy barrel and it had a perminantly attached flash suppresor which was approximately 5" in length. Because it was perminantly attached it was considered legal. Most of these had the retractable stock however mine did not. Mine had a standard fixed butt stock which was my choice. This was not an A-2 upper and did not have the fully adjustable rear sight. It had the short round handguards with the heat shields.

[BimmerJon]

AR15: pew....pew....pew
M4: pewpewpewpewpew