Complex sentence: The remote-controlled M85 machinegun was relatively ineffective in the anti-aircraft role for which it was designed compared to a conventional pintle mount, removing the cupola lowered the vehicle's relatively high silhouette.
Split into simpler sentences: The remote-controlled M85 machinegun was relatively ineffective in the anti-aircraft role for which it was designed compared to a conventional pintle mount. Removing the cupola lowered the vehicle's relatively high silhouette.