lets start with rangers 400 manpower 4xthompsons for 90ammo but they die quickly ,while paratroopers which are cheaper are better and 6 man squad and also have more abilities and weapon upgrades versatility more than rangers.
second the combined arms ability 125 ammo for increased range and accuracy (i think?) and all for little amount of time.
last we go with the pershing, cost lot of resources, have high upkeep ,it cost less pop cap but it also cant get out the crew for repairs, and Pershing do 160 dmg compared to Jackson do 200 dmg while also the Pershing ability cost 90 ammo and there is a chance not to reach is target and deliver 240 dmg while jackson can shot 3-4rounds with only 30 ammo of 240 dmg, 1 way of balancing the Pershing by lvl 2 add a coaxial 50.cal or increased health. or even damage.