I know an integral on an SBR or SBS makes it a 2 stamp gun  but being that DD is a different animal would an integral suppressor barrel for say a street sweeper be a second stamp   I'm guessing so but when I called tech they didn't know and transferred me to a voice mail

If the OAL of the bbl with the suppressor is 16"+  and it's permanently attached then it should be one stamp, for the can.

If it's less than 16" then it will be two. One for the can and one for the SBR.

+1

Barrel length has nothing to do with it.  Bore size > .50 (not exempted) + silencer = 2 stamps.

Hi from a DD dealer.

DDs have no barrel length rules.  It comes down entirely to bore size.  If it's a bore over 0.5" and it's not a "sporting shotgun" or a muzzle loader, it's a DD.

(Think about it- do you pay two taxes for one M203 because it has a 9" or 12" barrel?)

Suppressors, unless permanently mounted to an air gun, are another NFA item.  It used to be that permanently mounted suppressors were exempt.  For example, a MP5SD with a welded-on can was a "one tax gun."  ATF doesn't allow this any more but grandfathered the existing ones.  Most are getting removed, as suppressor technology has changed and MG buyers aren't worried about saving $200 on a $25k+ firearm any more.  

So, DD + Suppressor, whether or not permanently affixed and barrel length being meaningless, is two $200 taxes.

Mike

LOL!

Sorry guys... I was reading DD as Daniel Defense not Destructive Devices.

My bad...

(This explains the "street sweeper" reference...)

2 Stamps