Looking at Midway's website, it looks like either Bushmaster themselves or Midway has discontinued the following 450 Bushmaster items.
450 BM Barrels
Hornady 450 BM ammo
5rd 450BM magazines
10rd 450BM magazines
16 and 20" uppers are showing "unavailable - limited production" as well as Remington ammo.
Anyone have any insight on this?