Why Oh WHy

[stanc]

6mm SAW pushing a 105gr at 2500fps doesn't need that long of a case to do that, but it looks like they wanted to use aluminum cases to reduce weight, and had to line the aluminum with coatings to prevent aluminum combustion.

That resulted in a case with a 2.580" COL.

There were two different case lengths, with two different cartridge overall lengths. The aluminum case version (below, right) was 6x50mm, whereas the steel case version (below, left, and in the photo in my previous post) was 6x45mm. The shorter version was also made with brass cases.

That Ford Aerospace XM248 was a revolutionary LMG at every aspect of its design, with earlier versions designed to fire the 6x45 SAW. Its feed mechanism, recoil, overall layout, and parts count reduction were aggressive when looking at firearms design.

The more I study it, the more I really like what they were doing.

Indeed. A pity it didn't go further.