There is no way any soldier is going to carry this LMG with 100 rounds at all times, it is heavier than the SAW. Regardless, making this gun in .408 cheytac makes more sense.
>.408 cheytac can hit and kill better out to 2500 yards
>.408 cheytac is a bigger bullet than .277 fury, which means it will kill faster
>.408 cheytac requires less cost to produce than .277 fury
>.408 cheytac has a higher ballistic coefficient than .277
>.408 cheytac fmj is naturally armor piercing and can destroy a car engine
>.408 cheytac weighs 400grains while .277 fury weighs 135 grains
>You can make a bare bones lightweight cheytac LMG but not a lightweight .277 fury LMG due to the overpressured casing requiring more metal reinforcement
>.408 cheytac can kill easy out to 2500 yards
>cheytac has very little drop compared to fury and farther range which is perfect for combat in valleys and mountains and deserts
>cheytac can disable a engine block is less than 3 rounds
The weigh is heavy with the fury and carrying 200 rounds on their back and 100 on their LMG, have you seen the recoil on the xm250? goodluck shooting that accurately for bursts.
It would be overall better to carry a 50 round .408 cheytac LMG with 100 rounds extra, 50 on the LMG soldier and or 50 more on his battle buddy, the cheytac naturally has less recoil than the fury due to no overpressured rounds which will allow for more accurate follow up shots, including the high precision of .408 cheytac and the high ballistic coefficient, it would be much easier to use and with how heavy the bullet is would make it perfect for suppresive fire on vehicles and walls and homes