Actually by the time the U.S. joined both sides had relaized that bayonets were immensly impractical. You only used them in trenches where you had your movement restricted, yet you still had to wield a long, impractical rifle around to do anything with it. It was also very easy for it ro get stuck in a ribcage, making you vulnerable for a few seconds while you push your impaled enemy away with your foot. Instead they started making their own, mlre practical weapons. For instance the germans took their feldspaten (spades used to dig trenches with) and sharpened one end, turning it into an axe. That way you cut the enemy in the neck, severing an artery, it doesnt get stuck and they quickly eed to death. That way they weren't exposed for too long and could quickly mkve from one enemy to another. Others used clubbs, picks or knives made from scrap metal.
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TL;DR: bayonets were impractical and it was much more efficient to fight with a sharpened spade or knife or similar.
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TL;DR: bayonets were impractical and it was much more efficient to fight with a sharpened spade or knife or similar.