The difference between a M4 body and a M16 varient body...
 

I'm wondering.. What's the difference between a M4, a M16, and a M16vn body..

I'm thinking of upgrading to metal body sometime soon... And I feel it would be best for me to know what I'm getting into.. before I get into it.

I've got a m16VN... And I'm wondering if I need to get a M16VN specific receiver... Or if I can get a M4 receiver or anything like that..

Physically there are no differences in the lower. The only thing that changes are the markings on the left side of the receiver. The upper receiver can vary. The M16VN ought to have no forward assist, no case deflector, and A1 sights. An M16A1 receiver would add the forward assist. The M16A2 adds the case deflector and A2 adjustable sights. The base M4 would also use this profile. When you get to the M4A1 the upper turns to a Picatinny rail and may come with a detachable carry handle. Most "M4s" these days are all flat tops to begin with and it's turned into a very generic descriptor to describe most any short-barrelled M16.

So... I could put my VN mechbox in lets say.. a M4 metal body... And still use my M16VN's barrel?

Absolutely. Most aftermarket metal receivers though require a good amount of fitting, and in the case of Guarder Gen.2 receivers a MASSIVE amount of fitting. Not something you can just drop in and go. I believe the new Classic Army bodies with Armalite trademarks are relatively drop-in though and have the significant advantage of not using body tabs that can break off easily. Unless the trades turn you off you may want to explore that option first.

This is wrong.

TM VN uppers are very different from the A2 or M4 Uppers, and their outer barrel system is radically different. If you plan to upgrade to a metal body, you will need a new outer barrel, and IIRC a new nozzle, as the VNs is slightly longer than your standard M4/16's.

Agree with Goldman. The stock outer barrel system won't even work with an aftermarket VN body. If you want to stick with the VN style, I recommend getting the G&P VN metal body and the VN front end.

Being one of the first first first generation Armalites that Tokyo Marui produced, the design is fairly different to modern Armalites. Even accessing the gearbox is a bit of a pain in the butt and takedown occurs similar to a metal body installation where you attach the gearbox in the upper receiver first, followed by the lower.

Interesting, I never knew that. Thanks for the correction guys.

Ah! Thank you..

I'll look into this... The metal upgrade is not the biggest thing on my mind right now..

I'm more interested in getting the mechbox that I need...

By the way.. What's the cheapest route to go if I want to get a new barrel cover with rails on my VN? (And I don't think HOT GLUE is the best answer :D)

get a plastic A2 / M4 / SR16 plastic body, get a Marui RIS front end. That's the cheapest way to go.

if you want to go with the full length of the VN with rails, look in to an M5 solution, a G&P free floating barrel solution, etc etc.

The Hurricane M16A1 Metal Body will adapt to the TM M16VN's along with the newer M16's and M4's. Fitting to the outer barrel along with the mechbox is a breeze.

I've got one and it's solid as a rock.