during world war i, it was quickly recognized that the berthier's three-shot magazine was simply too small in comparison to foreign weapons, requiring too-frequent reloading. additionally, it was found that trench mud and grit could enter the weapon through the opening in the bottom of the magazine. to correct these issues, the model 1916 berthier rifle was introduced with a five-round en-bloc clip. the clip discharge opening at the bottom of the protruding magazine was replaced by a spring loaded trapdoor to keep out dirt and debris. this improved 5-shot design was then fitted to existing rifle and carbine-length berthier models (mle 1907/15, mle 1890m16, 1892m16 and mle 1916 ""mousquetons"" ). in response to changing combat situations at the front, which had evolved from a war of maneuever into static trench warfare and frequent night raids, many berthier rifles were also fitted with sights designed specifically for close range or night combat, using radium paint to improve visibility in poor light or darkness.