Protecting HMs frontiers, via Vickers
While the sun may have never set on the British Empire (until 1956, anyway), the Brits were big fans of using technology to their advantage to allow units with small footprints to control large areas.
From 1912 through the 1950s, the water-cooled .303 caliber sustained fire Maxim machine gun variant produced by Vickers Limited, best known just as the Vickers, filled the bill.
Weighing in at over 40-pounds (sans bullets and water) old Mr. Vick was a beast, but by nature of its water jacket could fire almost forever or until your ammo supply ran out, making a static defense point able to control everything in a 360 degree arc out to 1,000 yards with accuracy, with grazing fire a death sentence for infantry trying to move on the emplacement.
When using plunging fire, especially when sited from elevated positions, the Vickers could reach out and produce a beaten zone over 4,000 yards away. As such, these guns were equipped with pretty effective and advanced for their time clinometers on which trained crews could calculate angles of slope (or tilt), elevation or depression of their target and match their gun to make an intersection of brass and body.
It was simple, the machine gun in its truest form.
The Vickers was only replaced in the 1960s by the FN MAG 58, termed the L7 General Purpose Machine Gun (GPMG), which has been affectionately nicknamed the “gimpy” by generations of British troops.
Mr. Vick, however, endures in the armories of many former British colonies. While no longer actively used, the 100+ year old design is still an effective defensive machine gun if needed as long you bring the water and .303.