[MasterGunner01]

Shooting full power ammunition in the .30-06, .303 British, 7.92x57, or 7.62x54R on full automatic and retain control is a broblem of basic physics. There are muzzle brakes that can cut-down the recoil (a .30-06 produces 15-18 ft-lbs) and a compensator can help with muzzle rise, but you simply cannot put this kind of power in a 6.5 lb. rifle. Certainly not on full auto and with any kind of control.

The standard select fire FN FAL or M14 weighs in at 12 lbs and can't hit the broadside of a barn on full auto. The US Army spent millions of dollars in the late 1940s and early 1950s trying to prove it could and the laws of physic proved them wrong.

[donmeaker]

Cut the rate of fire in half, and you cut the average recoil in half.

Spread the recoil force out, as with a long recoil operating system, and you make it possible to compensate for its operation with a steady push.

And reduce the rate of fire, and your ammunition usage is reduced.

As you say, simple physics.