The aluminum case was first designed using the same dimensions as the Brass/steel case 6×45 SAW versions and later redesigned and manufactured with a lengthened body to accommodate a silicone Flexible Internal Element (FIE) to prevent burn through but still provide enough propellant space equal to the original 6×45 SAW case.

This bottom version is a drill/inert loading hence the blackened primer. The case is loaded with an inert white granular ballast (sodium carbonate) and there is no silicone internal element inserted.