Does anyone sell a government/m4 profile barrel without threads? Looking for a 16" with a carbine gas system.

Not sure if any of these are specifically what you're looking for, I think I remember seeing something like that in my many searches.

 

http://www.bushmaster.com/products.asp?cat=7

 

http://www.brownells.com/.aspx/pid=42974/Product/UPPER-RECEIVER-BARREL-ASSEMBLIES

 

This is a full upper, but if you can find the barrel, it (might?) be what you're looking for.

 

http://www.del-ton.com/AR_15_Barrel_Assembly_p/dt1015.htm

 

This is 20", but I imagine they make a 16" (Usually, for me at least, 20" is harder to find..)

 

http://www.del-ton.com/Del_Ton_Barrels_p/bl1014.htm

 

 

Wait... here's a 16"

http://www.del-ton.com/Del_Ton_Barrels_p/bl1012.htm

 

I'm not sure if this is the stuff you're looking for, I'm no expert on the difference between the M4 style systems, and the Ar15 ones, but hopefully something here will be of use.