Complex sentence: The BL 8-Inch Howitzer Mk 1 through Mk 5 was a British improvisation developed early in WWI to provide heavy artillery, using bored-out and shortened 6 inch naval gun barrels instead of a true howitzer barrel.
Split into simpler sentences: The BL 8-Inch Howitzer Mk 1 through Mk 5 was a British improvisation developed early in WWI to provide heavy artillery. It utilized bored-out and shortened 6 inch naval gun barrels instead of a true howitzer barrel.