Given the prevalence of muddy horrible trenches in World War 1, why didn’t anybody design dust covers to protect the actions of their combat rifles? Well, they actually did… and today we are looking at both French and German examples.
The French model was a very simple contoured sheet metal shield attached to the rifle by the bolt head screw. Introduced in mid 1915, versions were made for both the Lebel and Berthier rifles. In fact, the cover (called a couvre culasse in French) was originally incorporated as part of the M1916 upgrades to the Berthier, along with the 5-round magazine and upper handguard. However, it was dropped from use for some reason, leaving only the enlarged bolt head screw as evidence of its passing.
The German military took longer to develop a suitable dust cover, having started with a cloth model that was too good at retaining moisture and caused rusting on guns. The first metal version developed was judged inadequate by the testing commission (probably because it was clumsy to remove and had to be removed to actually cycle the bolt). An effective design finally appeared in 1917, but only small numbers appear to have made it to the front lines before the end of the war, in part because of endemic material shortages.