Just to be nit-picky : the gatling is stated as being a 8x50mm and sold as an "antipersonnel" weapon system. 50mm gatling to mow down infantry is slightly overkill if you ask me since the barrels look smaller than that of the left-side autocannon, I was wondering if that was not a typo.
I would concur with both of these points. The gatling looks more like a 30mm, and even in the future, 30mm DU APDS rounds should still tear through "light" armored APC's and such. As an ex-CIWS tech, our Phalanx gun was 20mm (later upgraded) and fired ball ammo or APDS sub-caliber 20mm depleted uranium rounds. One thing with firing non-discarding sabot ammo is the high rate of barrel wear and corresponding cleaning and maintenance. The use of sabot rounds greatly decreases wear and tear.