Complex sentence: He was hit several times and fell to his knees when within 25 yards of his objective; but he summoned his waning strength and emptied his rifle into the machinegun nest, silencing the weapon before he died.
Split into simpler sentences: He was hit several times and fell to his knees when within 25 yards of his objective. However, he summoned his waning strength and emptied his rifle into the machinegun nest, silencing the weapon before he died.