Please note: On above picture on Right side Left to right: 6.5mm SAUM, 7mm SAUM, .300 SAUM

LIMIT ONE CARTRIDGE PER CUSTOMER FOR THIS ITEM.

One Cartridge, not a box:  6.5mm Remington Short Action Ultra Magnum. Wildcat ? Also called the 6.5 SAUM for short. Produced by Prime Ammunition Company using new Prime brass cases and loaded with 142 grain HPBT (Hollow Point Boat-Tail) projectile.  

History of the 6.5mm Remington Short Action Ultra Magnum. Wildcat ?:
I am unable to find a SAAMI rating on the 6.5mm Remington Short Action Ultra Magnum, so I consider it a wildcat even if produced by a small manufacturer, I well you ideas.
The 6.5mm Remington Short Action Ultra Magnum (6.5 SAUM) for short, but not to be confused  with the 6.5 Remington Magnum was produced by necking down the 300 Remington SAUM to increase velocity and a better short flatter at long ranges then the 7mm Remington SAUM (also necked down 300 Remington SAUM) . As of this writing I have no idea what the “4S” in the headstamp refers too.

History of the 7mm and 300 Remington SAUM:
The 300 Remington Short Action Ultra Magnum (SAUM) was introduced in 2001 to compete in the same field as the Winchester .300 Winchester Short  Magnum (WSM).
Short magnums were first introduced by the Lazzeroni Rifle Company, and are designed to operate in rifles with short actions to get long action performance  by utilizing wider cartridge cases bodies to hold more gunpowder.
Winchester basically copied Lazzeroni's ideas and introduced the Winchester Short Magnums (WSM) and Winchester Super Short Magnums (WSSM) in early 2000 and Remington followed with the 300 Remington Short Auction Utlra Magnum (Remington SAUM) in 2001 and later in 2001 with the 7mm Remington SAUM.