Also, in the picture with the M256 there are two unicorns hiding at the very top behind the GBU-28 Paveway (which, as we know, was partially built out of decommissioned 203mm howitzer barrels from the now-retired M110A2 - hence its presence in the room) and the orange scissor lift:
- Either the 58-caliber XM282 or the 39-caliber XM283 (based on the M198's M199) that were trialed in 1985 for the Howitzer Improvement Program (HIP); there were three guns proposed as part of the Advanced Armament System (AAS): the XM282, the XM283 (both 282 and 283 were fitted onto five M109A3E3 testbeds) and the XM284 (fitted onto four M109A3E2 testbeds). They eventually selected the XM284 for what ultimately became the M109A5. The howitzer gun on this picture looks like the XM283, but with the barrel length, it's more like a L58 XM282 (which had a chamber volume of 27.8L/1,700 cubic inches and could lob M549A1 HERA projectiles up to 45km with the XM224 propellant charge). Also note that they also cut a XM282's barrel down to 52 calibers to test liquid propellants; that L52 could also be the one seen here.
- Right next to it is the L56 XM297 (chamber volume of 1,400 cubic inches) that was installed on the Crusader (which also, at one point, dabbled with liquid props before switching back to solid MACS propellant charges). Easily recognizable with its pepperpot muzzle brake.