Mid-length 5R Barrel?

[Wumpus]

So I see where S&W are now making a model -15 of the with the same nitrided, 5R, 1/8 barrel as the Sport, but in a middy...

Anybody know if they'd sell the barrel by itself? Or maybe a complete upper? I kinda like the 5R and 1/8 twist. A 16" Mid-length might be an option to try instead of an going with somebody else's 18" or 20" upper...

 

[oneyeopn]

I asked them not to long ago about it and they said that they didnt sell the barrel in anything but a 16 inch length...I was trying to find out about a 20" for a dream varmint looooong range weapon.