What's the difference between a 16" Bushmaster Shorty barrel and a M4 barrel? I'm a newbee..

The Bushmaster 16" shorty has the full heavy profile under the hadguards.  The M4 barrel has the lightweight profile under the handguards, plus the cutout for the M203 grenade launcher.  Plus the real M4 barrel is only 14.5" although Bushmaster also makes a 16" version.

M4:
[img]http://www.bushmaster.com/shopping/barrel-assemblies/Images/abbl14m4a.gif[/img]

16" shorty:
[img]http://www.bushmaster.com/shopping/barrel-assemblies/Images/16shrtybbl_small.gif[/img]

16" M4:
[img]http://www.bushmaster.com/shopping/barrel-assemblies/Images/pbbl16m4a.gif[/img]

Okay, I'm not an M4 guy, but I'll take a shot at it.

A true M4 barrel is 14.5" long, has a bayonet lug, a flash hider and is contoured to accept a grenade launcher. Available to military, police and licensed individuals only, because the barrel is less than 16" overall.

The M4 barrel available to us common folk is 16" overall length including the muzzle break (flash hider for a pre ban lower reciever). No bayonet lug (pre ban can have one). Purely cosmetic.

But looks good, even if it is fake.

By the way, rifles in this configuration are commonly known around here as M4geries.

Operator Error.

Isnt it possible to own a 14.5" M4 preban when it s registered as a SBR. And C3 is also a another matter in itself.

Proud owner of a 14.5" Bushmaster M4A3. No such thing as a "preban and "postban" here.

Tuukka,

I used the term "licensed individuals" as an all inclusive, generalized term. Mainly because I don't really understand all the Class 3 rules, and I really think that explaining them would be better left to an expert.

Yes, if you live in a free state, you can probably pay the tax and make a short barreled rifle.

I think my chances of being allowed to do that in CA are pretty slim.

Can I emigrate from California to Finland?

Ahh, didnt spot that part there.

Your welcome here :). Summer´s just beginning to get rolling.