Impact of Gebauer machine gun.

From little information available on the internet, this gun seem to be almost perfect cowl gun. High rate of fire, Can be adapted to .50 caliber and reliable.
Would this gun be a game changer if the Axis nations adopted it?

Axis' main faults were done on the Grand Strategy level. If they still make war on whole world while not having means & strategy to do it, they still loose, badly.

On a technical level you had a two barrel gun firing 2600rpm (some sources say 2000rpm) of 7.9mm ammo.
Most countries by 1938/39 had single barrel rifle caliber guns that could fire 1000-1200rpm. AN extra 30% (if it was the 2600rpm) rate of fire won't really change things by a huge amount,
especially considering that the 7.9mm Gebauer was supposed to weigh 93lbs.
That is about the weight of four Colt-Brownings or four MG 17s, so the Gebauer doesn't actually get you much of anything at all.