I have attached two photos of an experimental SFM 20 x 127mm case. I have had it for years and don't know anything about it. Can someone tell me what it was meant for and what projectiles were loaded in it? Sorry about the photos, but for some reason the camera decided that it didn't want to focus when I wanted it to. The headstamp is 20 DCA - 5CG SF - 1 - 54 - 1. Bob