We go to sams every week, and I can never remember them being out of butts. They always have the 2 packs. Occasionally they run out of packer briskets, but usually they have them within a few days. Last weekend they had about 40 of the 2-pack butts on display, and only one packer brisket ( 16lbs ). If I remember correctly the butts here are the Smithfield bone in butts. The packers are always EXCEL brand.
One more thing our sams always has is chuck roasts. You can usually get 2 nice roasts for about 18.00.