260 Remington SA Ultra Mag

I got this cartridge last year at the Gary Hoffman auction but there is nothing I can find on the internet regarding the 260 Remington SA Ultra Mag. Dimensions are exactly the same as the 7mm RSAUM, except for the bullet which measures .264". Was this something just never went past the test phase?

260%20REM%20ULTRA%20MAG 260%20REM%20ULTRA%20MAG%20FULL


Better known as 6.5 SAUM…check that out on i-net may find more information.