Lets say that I have a AR15 Pistol that I assembled from a "virgin" receiver.

I build the pistol with a 11.5" bbl and use a M4 buffer tube.

Now I get a registered suppressor that ADDS at least 5" to the OAL of the barrel.

Under the TC Contender rulings, couldn't I install a M4 stock after the suppressor is installed providing that I remove it prior to removing the suppressor since the OAL of the barrel would be over 16" any time the suppressor is installed?

Quoted: Lets say that I have a AR15 Pistol that I assembled from a "virgin" receiver. I build the pistol with a 11.5" bbl and use a M4 buffer tube. Now I get a registered suppressor that ADDS at least 5" to the OAL of the barrel. Under the TC Contender rulings, couldn't I install a M4 stock after the suppressor is installed providing that I remove it prior to removing the suppressor since the OAL of the barrel would be over 16" any time the suppressor is installed?

It would have to be permanently attached

A handgun may goto a rifle and back to a handgun willy nilly.

Weld the silencer onto the barrel and it's over 16" legal for a std. rifle.

Take handgun, put on silenced upper, put on buttstock and it's a rifle.

Take off buttstock take off silenced upper put on pistol upper and buffer tube one, it's a pistol.

Take off silenced upper, put on pistol upper forget to remove buttstock, goto jail.

Unless your state/local does not allow short rifles I would just go with that instead of a pistol.

I think you guys are missing the point.

1. To legally avoid having to invest another $200 in my carbine.
2. To easliy switch between rifle/pistol without swapping uppers.

Let's muddy the waters a little more.

Let's say that I have the same "pistol" lower with a M4 extention.

Now I buy a LMT MRP upper with a 10.5" bbl and install that.

I now have a totally legal AR15 pistol. I don't think anyone will contest that. (assume I have no other AR's and there is no "constructive possesion" of any other AR parts.

Now I decide that I want a little more punch and buy a LMT 16" barrel for the MRP. As soon as I install the 16" barrel, I can legally install the buttstock because the "pistol" will now be a legal rifle. This is also a point that no one can really argue against.

How does this differ from installing a suppressor on a pistol to increase the barrel length to a legal 16" OAL, then installing the buttstock?

As I said this is really an academic discussion anyway since I am buying a new stripped lower to register as a SBR.

It just dosent make sense that replaceing the whole barrel would be ok on a "quick change" system like the MRP, but screwing on a suppressor would not on a standard barrel.

I understand the permenantly attached muzzle device on a RIFLE since a Rifle can ONLY be a Rifle unless registered as a SBR or equipped with a RDIAS or RLL. But something that can be switched back and forth as in the TCC ruling would seem to be exepmt from this as long as it has all the parts to make two legal versions of the weapon.

Quoted: I think you guys are missing the point. 1. To legally avoid having to invest another $200 in my carbine. 2. To easliy switch between rifle/pistol without swapping uppers. Let's muddy the waters a little more. Let's say that I have the same "pistol" lower with a M4 extention. Now I buy a LMT MRP upper with a 10.5" bbl and install that. I now have a totally legal AR15 pistol. I don't think anyone will contest that. (assume I have no other AR's and there is no "constructive possesion" of any other AR parts.

I'm not so sure about that.  I thought you couldn't put an M4 extension on a pistol.  If it's got the channel and holes to allow the stock to work then it's a no go on a pistol.  This is why companies go to the trouble of makinng pistol extensions.

Regarding your barrel question, you've got your answer.  Adding something removable to a barrel is not the same changing to a longer barrel.  It doesn't really matter what you or I think about that, it's what the BATFE thinks about it and they say no.