I replied on another site to the same poster, but will do it here also. The design of that gun was not bad, the problems being mostly in poor manufacturing techniques and quality control, plus the problems arising from the terrible 8mm Lebel cartridge. Made originally and correctly for a round like the 8x57 or .30-'06, it would probably have been a pretty good gun.
But the whole idea of an "assault rifle" or "marching fire" was tragically disastrous. It might have worked in the Civil War against rifle-muskets without artillery support,* but in the WWI context, the idea that veteran troops, solidly entrenched and supported by machineguns, will duck down and allow themselves to be overrun just because the attacking enemy is firing had to be some general's pipe dream.
The worst, and silliest, ramification of that idea was the Pedersen device, which was supposed to cause enemy soldiers to hunker down and cover up in response to firing such a low power cartridge that they wouldn't even have known they were being fired on. Fortunately, the war ended before thousands of American soldiers were slaughtered proving that Pedersen's idea was ingenious, but didn't belong in a real war.
*For evidence that it didn't even work in the Civil War against entrenched troops supported by artillery, have a chat (if it can be arranged) with one Maj. Gen. George Pickett, CSA, who had some personal experience in that line.
Jim