ID needed. 3"x600MM Brass casing

[917601]

I just received this one. Not a US Navy 3"/50, not a US Army 3 in MK II M2. It looks like the Army 3in in the shoulder but is taller. It is also taller then the Navy 3"/50. My measurements: 76mm ( 3 in) X 600 mm. Headstsmping: " 3 IN MARK II, Gun MOD OF 98-02-18, AMM LOT, 1501, Lot 1379 25- F.P.S., small number 28, small crossed cannon flaming bomb,primer unreadable. Brass, neck has a few cracks. Pictured center, next to Army steel 3in and Navy 3in ( with projectile). WW1?

 

[HAZORD]

It's for the older Army 3" AAA gun that used projectiles with smaller rotating bands. There are postings on BOCN about all 4 cases. The older WWI guns used rotating bands that were 1/2 inch high. They had a slower twist rifling. Some of these guns were used in WWII for seacoast defense and training. When they designed the WWII guns, they had a faster rifling twist and bigger rotating bands to spin the projos faster, but kept the same overall chamber length. More rotating band meant shorter case length.

http://www.bocn.co.uk/vbforum/threads/38079-3IN-Case-ID?highlight=inch

We are in America. Use inches. All the Military manuals are in inches.