Hmmm 2,000 meters sounds good.
Range about 1.3 miles.
Aim a little high.
A shot in the dark here. Would titanium enhance barrel endurance at a cost that is sustainable for military purchases?
If brittleness issues could be overcome, ceramics could provide long rates of sustained fire and eliminate corrosion concerns.
2000m effective range in a M240 sized package is a tall order. It has been a challenge to keep the ragheads beyond the range of their weapons without having to haul a M2 or Javelin.
Heat mitigation- aggressive fluting multiplies surface area while providing additional stiffness to the barrel.
Light weight- aggressive fluting removes mass while increasing surface area
2000m effective ranges? Hmmm, not the 762x51, they mention 6.5 Creedmore- but while that is a step up in terms of better external ballistics, it is a step down in terms of total KE/Momentum at the target, even with very heavy fro caliber ( 160-180 grain bullets- the trade off is big for increased mass of projectile to overall performance on target. Better than the 762in the end though.
durability- carbon steel salt bath nitrided in and out provides a much tougher barrel regarding erosion from powder gases, could triple barrel life; also new ceramic-metallic coating ( Cermet) may be able to provide both less friction and more barrel life as well as less heat build up ( less friction).
Operating system/recoil management- gas operated systems steal some energy to operate the mechanism, well and good but that energy is used at the expense of the downrange effect. The operating mass eats up some recoil. Perhaps a recoil operated system with a floating receiver/barrel/bolt inside a shell body/buttstock would attenuate recoil better-and does not use propellant energy to operate. Heat has to go somewhere too. Out the muzzle behind a bullet is better than back as heat (energy) into the mechanism...
Downside to recoil operated mechanism is non-adjustable operating mechanism.
the trend to short barrels is the long pole on the tent, so perhaps a bullpup configuration with a 26 “ barrel ( where the 6.5 really shines) may be needed, keeping the OAl within comfortable handling realm.
Think of a 1919 or M2 type mechanism ( recoil operated) inside a shell so the whole of it floats on a recoil attenuation system- recoil is used to operate and is delayed to the firer as the mechanism in operation moves rearward in the shell.
Where are John M. and Eugene S. when you need them?
Ah yes. The machine gun made of unobtainium. Everything we ever wanted in a mg, even the “long life” barrel.