2015 Hodgdon's Annual Manual has an article on the .26 Nosler - seems to me, the 2016 Annual Manual has an article on the .28 Version - both using the RUM case, shortened somewhat to 2.5 or 2.6" or so. I don't have the exact numbers. Seems to me, they wanted it to work through a standard action, with an overall length of 3.340".