An infantry AT weapon that sacrifices range for penetrating power would be a good idea, the thing with most modern infantry AT weapon is that their range are unnecessarily long and don't have enough penetrating power, engaging enemy armour at the range of 300m shouldn't be the job of light infantry, they should fight enemy tanks in close terrain, so, it will be best for them to have a weapon with a range of 50m and be able to penetrate the side armour of modern MBT's potentially fitted with ERA.
see those M72 SRAW? You seriously think that you can hit a moving tank 300m away with those flip up sights?