Throughout the history of firearms, there have been plenty of weapons that were more for show more than they were useful. Many of these historical oddities never left the prototype phase and end up serving more as collector's items. Others, however, made it into the hands of troops and earned reputations as duds.
As much as troops gripe about the small flaws in the weapons they're issued, they can take solace knowing that they were never issued a Chauchat Light Machine Gun.
It was designed before WWI as one of the first light, automatic rifle-caliber weapons designed to be operated by a single troop. Before troops got their hands on the majesty that is the M1918 Browning Automatic Rifle, the Chauchat made due.
There were three major flaws with the Chauchat. The first and most glaring shortcoming is the magazine. The designers decided the magazine should have an "open design" to allow operators to see how many rounds they had left. This was pointless as the firearm shot 250 rounds per minute and the magazine only held 20 rounds. Basically, this hole just allowed mud and gunk to jam the weapon.
Even under pleasant conditions, this light machine gun is heavily flawed. The long recoil system mixed with its extremely loose bi-pod meant that troops couldn't maintain anything more than very short bursts. But, a short burst of fire is all you were likely to get, given the amount of cartridges that fail to eject from the chamber...
If, somehow, you managed to keep it perfectly clean, only loaded 18 rounds to avoid the first-round, failure-to-feed problem, and you got lucky with cartridges "stovepiping," you'd still run into such serious overheating that it causes the barrel sleeve assembly to lock in the rear position until it completely cools down.
All of these problems were made worse in the American Expeditionary Forces version of the Chauchat, which were chambered in .30-06 instead of the 8mm Lebel. This version's chamber was also incorrectly measured which meant the weapon was, essentially, useless.
Despite all of its flaws, the Chauchat set the groundwork and laid out the problems to fix when it came time to field the M1918 BAR. For more information on the M1915 CSRG, commonly called the Chauchat, check out the video below.