The A2 has been around for a long time and is a stable for the US army. The M4 has been adopted by various SPEC OPS forces...for the real steel info, ask Lupo...he knows a lot more about it than I do.

The airsoft versions of both guns are pretty new, no more than 2.5 yrs old. I owned an M4 and is in the process of building another project gun based on one. I've also worked on many M4s as a lot of ppl like them.

Gun Type: M4- Carbine M16A2- Full Rifle Mechbox: VER II

Battery: Mini or Large Lowcap: 68 Hicap: 300 or 190

Ok...let me start off by explaining the reason behind discussion these 2 guns together...the reason is that the guns are the same except the different length front ends, and the upper receiver(M4 has flat top rail and removable handle) They were released one after another, and the parts are pretty much interchangeable with each other. Just think of the A2 as a full rifle version of the M4. This review will mostly be about the M4 with a few M16A2 bits here and there.

The M4 hit the market about 2 yrs ago, and I was one of the first people to own one. (I think I could be the first to own one in NA as mine was shipped directly from HK from the first batch...I got mine 4 months b4 APEC had them) It was the long awaited new model that everyone talked about. I've always been an M16 fan and was one of those anxious ppl as well. Upon receipt of the gun, I was amazed with the weight and attention to details that surpassed my previous XM.

Shooting: The gun is very comfortable to shoot, its carbine length makes it fairly manuverable while offering decent range and accuracy.

It tends to be front heavy as most of the metal parts are in the front as well as the small battery in the foregrip.

Mag changes are lighting fast as it's a simple push of the button for right handers. The mags just fall right out and they're not too large to handle. This IS the slickest mag change of all AEGs.

The sights are pretty shitty...I hated using the sights as they take forever to line up a target, having said that, this gun is pretty easy to pt shoot due to its relatively small size.

Upgrades: This gun is probably the grand poopa of upgradeabilty (even better than MP5) There are so many parts and so much different stuff (both real steel and airsoft) that the different possibilities are mind blowing. You've all seen Lupo's Bushmaster rifle and various other ppl have made different project guns. RISs, metal bodies, foregrips...you name it, u can get it.

Internal upgrades: are also quite abundant as it uses the popular VER II mechbox...much like the G3, this baby can be made into a sniper gun.

Quirks: Sad but true, this gun has MANY quirks. It's prone to the infamous "front barrel wobble" as well as broken plastic body parts...especially the "tabs" on the upper receiver of the body. The first problem can be addressed by using metal foregrips or by installing "anti wobble outter barrels"...either one of these options will run you at least $75. The broken tab problem can be addressed by using a metal body, but the good metal bodies built by Systema cost as much as the gun itself...(note: DON'T buy CA metal bodies for M4/ M16A2, they're SHIT!!!) Other than that, there is a minor problem of the hop up that needs constant adjustment...(the metal one that comes with the systema body fixes this...it can be purchased by itself)

Batteries: Most of you guys that upgraded the M4 know about the "U" shaped 1500-1700mAh batteries available. They're good batteries and serve the purpose well. Your other option would be to get an A2 full stock...but they're rare and expensive.

Overall, I recommend this gun due to its versability...however this gun needs constant maintenance or expensive parts to make it really reliable. If you don't have a lot of coin to blow and still want to build a top notch field gun, go with an MP5 or G3 instead.