By the end of WW1 most of the major powers had indeed developed semi-auto rifles and were used to some degree or other.
However aside from the US most reverted back to bolt-actions by the start of WW2 how could that aspect have been changed and what real impact would there have been?
However aside from the US most reverted back to bolt-actions by the start of WW2 how could that aspect have been changed and what real impact would there have been?