This only really applies to the AR57 upper receiver, but in cases where you have a monolithic upper with an integral ~10" handguard (such as the AR57, where the handguard is the same chunk of aluminum as the upper receiver) and a barrel shorter than said handguard (for putting a linear comp or suppressor underneath the handguard), where would you measure OAL from? I would assume the muzzle (or the end of a permanently attached muzzle device), but if you can't remove the handguard without cutting the upper receiver in half, would you measure from the forwardmost non-removable portion of the weapon? This is concerning legal OAL (to determine whether you can use a VFG or if it's a "pistol" or a "firearm"), obviously you'd measure from extreme end to extreme end to determine what size case it would fit in. If only the law were that logical

I would argue yes. By attaching a flash hider permanently they agree that the OAL is extended. It is still a flash hider and not a barrel, and now they measure from that point because it is permanent. So by that same argument the permanent extension of the firearm receiver would be just as valid in OAL as a muzzle device.

Your argument makes sense, EXCEPT for the fact the BATFE has specifically said to use the end of the barrel, without including muzzle devices, unless those muzzle devices are permanently attached to the barrel.

Now, I do realize when the BATFE made that ruling monolithic uppers probably did not exist. And now that monolithic uppers do exist, perhaps the BATFE will revise the wording. But until then, I would go by what the BATFE has specified; to the end of the barrel, without the muzzle device, unless the muzzle device is permanently attached.

But, in any case, please do not write the BATFE a letter!

I seem to remember seeing a mfr who made an upper w/ a short barrel and a free float tube which was permanently attached to meet the barrel length requirement.    The explanation I remember reading was that it gave you the short barrel where you could attach a suppressor which ran to about the end of the tube, but not have to have the stamp for the SBR.  Anyone else remember seeing that?

Makes no sense. Barrel is required to be 16" for a non-NFA rifle.  The only thing extra that can become part of the barrel is a permanently attached muzzle device. You can permanently attach anything else you want to a barrel, but it doesn't become part of the barrel.

- OS

You mean this?

Notice the shroud is still attached permanently to the barrel, not the receiver.

That's not the one I remember, but that's probably what they had.  

OP, I'd say no, because they say 16" barrel, and the placement of the barrel in the firearm doesn't matter. As in, a Tavor is a lot shorter than an AR even if both have a 16" barrel. Because of options like the Tavor and others, it's probably better NOT to persue this, or else they'll create some sort of hindering rule saying a gun has to be X inches past X point of the gun, rather than a min OAL and barrel length.