Complex sentence: The turret mounted the Ordnance QF 17-pounder gun required in the Tank Board specification and the hull machine gun was removed to provide stowage space for the long 17-pounder cartridges.
Split into simpler sentences: The turret mounted the Ordnance QF 17-pounder gun required in the Tank Board specification. The hull machine gun was removed to provide stowage space for the long 17 pounder cartridges.