Re: 155 scenar in combat
The 155 Scenar can be a viable military bullet.
US military reluctance comes from limited application (in 7.62mm it does best with barrels longer than 24-inches to take advantage of the BC, and in shorter carbine barrels it takes up more case space, again cutting back on velocity). It is also tons more expensive than run-of-the-mill GI Ball. You run into a return-on-investment wall when talking about capability for cost and quantity.
135-grain Match Kings are a fairly good match in shorter carbine barrels to 300-Meters -- better accuracy and faster than 147-grain GI M80 machinegun ball, 168 Match Kings, and 175s.