Complex sentence: However, while the Pak 38 made extensive use of light alloys to reduce overall gun weight, these were now earmarked for "Luftwaffe" use and the Pak 40 used steel throughout and was proportionally heavier than the 5 cm model.
Split into simpler sentences: However, while the Pak 38 made extensive use of light alloys to reduce overall gun weight, these were now earmarked for "Luftwaffe". As a result, the Pak 40 used steel throughout its construction and was proportionally heavier than the 5 cm model.