>>592822
Anything that big and heavy needs to be self-propelled today, and as others pointed out, you have weapons with similar firepower that can be be moved and operated by a single man.
>>592831
I'm not sure why'd you want to use such weapons against vehicles, but the Russians seem to came up with a solution to the problem of long time of flight:
http://www.military-today.com/artillery/2s31_vena.htm
>This mortar system can be used as mortar or howitzer, delivering direct or indirect fire. Maximum range of fire is 7.2 km with mortar mines and 13 km with gun shells. Various munitions can be used, including HEAT, HE-FRAG, smoke. Vena is compatible with all munitions, developed for the Soviet/Russian 120 mm combined gun/mortar systems. It can also fire any 120 mm mortar rounds.
Or if we want something more esoteric, then take a look at high-low cannons:
https://en.wikipedia.org/wiki/8_cm_PAW_600
>Because the ammunition was developed from the standard infantry mortar, any type of round developed for the mortar could have been readily adapted for the 8H63, including high-explosive (HE), smoke and illuminating rounds. The HE round, the 8 cm W Gr Patr 5071 with a 4.46 kg projectile and total round weight of 8.30 kg was developed. This could employ three different charge increments for maximum ranges of 3,400 meters @ 220 mps, 5,600 meters @ 320 mps or 6,200 meters at 420 mps - about three times the range of the mortar and with the possibility of direct or indirect fire.
81mm mortars have a muzzle velocity of 220m/s, so it would be faster. And you could scale it up to 120mm.
>>592824
Are those five and six pointed starts that are painted on to act as camo?