Complex sentence: During the first four years, the factory produced 2,000 long guns, while in 1814, the output grew up to 10,000 guns and almost 2,500 backswords.
Split into simpler sentences: During the first four years, the factory produced 2,000 long guns. In 1814, the output grew up to 10,000 guns and almost 2,500 backswords.