In early 2016 American troops began receiving the latest version of the standard ACH combat helmet. The new LW-ACH (Lightweight Advanced Combat Helmet) is 10 percent lighter than the 1.5 kg (3.3 pound) ACH and has improved protection and comfort. Even before delivery of 105,000 LW-ACH helmets was completed (in late 2017) a lighter version of the ACH, the ACH Generation II was announced which is lighter still, has improved protection and easier to wear. The ACH Gen II will begin appearing in 2018 and it weighs about the same as the World War II M1 helmet. That last bit is what interests most troops as the weight of equipment troops are required to wear has been increasing since the 1980s and has reached the point where it is considered a health problem. While the troops appreciate the much improved protection from combat wounds most troops in a combat zone are unlikely to even come under fire. Yet they are ordered to wear the increasingly heavy (and dangerously hot) protective gear by commanders more concerned with media criticism than the welfare of their troops.
One of the main proponents lightning the load has been SOCOM (Special Operations Command) Thus it is no coincidence that around the same time ACH Gen II is introduced SOCOM will begin receiving the Caiman Carbon Bump Helmet System, which is a modular helmet that can weigh under half what the ACH does or, with easily affixed modules weigh about the same as the latest ACH and be more comfortable to wear. This modular helmet may well be the next big thing for all infantry, as were so many other infantry innovations pioneered by SOCOM.
Comfort is important because in combat troops wear the helmet up to 18 hours at a time and uncomfortable helmets cause fatigue and reduce reaction time. For that reason SOCOM operators sometimes go into action with no helmet. But with the widespread use of personal radio systems, first by SOCOM and now by most American troops, some kind of lightweight helmet became necessary. Since the 1990s SOCOM has led the way in development of lighter and more efficient helmets because they always had freedom (and cash) to try anything. The army and marines followed these SOCOM developments and are quick to adopt the ones that were suitable.
Meanwhile the heavy helmet also has an interesting history. The World War II M1 helmet was replaced by welcome new designs in the 1980s but those new models kept getting heavier and after 2001, as more American troops spent a lot of time in combat, weight became a major issue. It wasn’t just the helmets. Since the 1960s improved body armor has reduced casualties by more than half. But this meant that combat troops had carry more weight because the new protective vests and helmets were heavier. Going into the 21st century the developers of the vests had to concentrate on weight and ease of use as well as protection.
The protective vests used in Vietnam and late in the Korean War reduced casualties by about 25 percent compared to World War II and improved vests and helmets meant that by the 1990s the risk of getting killed or wounded has been cut in half since World War II. Much better medical care (especially rapid evacuation of casualties by helicopter) has made a major contribution as well and that meant the ratio of combat dead to wounded went from 1:3 during World War II to 1:7 today.
New helmets attracted a lot of attention be after 2005, when American military personnel began using a new helmet design (ACH) that offered unprecedented protection something unprecedented happened. For the first time troops had a helmet that stopped most sniper bullets and nearly everything else. This was a tremendous boost to morale, especially because there were more and more incidents of soldiers shot in the head and surviving because of ACH. At first troops were wary of reports of ACH stopping high powered 7.62mm sniper rifle bullets. But the army distributed pictures of the helmets that stopped sniper bullets as well as statements by the soldiers who were wearing them when hit. While the media ate this up, releasing all this data was mainly for the troops.
All this is part of an ongoing trend because since 2000 combat helmet design has made enormous advances. The new helmets have increased protection (often against high speed rifle bullets favored by snipers) while becoming more comfortable to wear, more accommodating of accessories (especially personal radios and night vision gear) without becoming heavier. Combat helmets were long considered low-tech but that has changed since the 1980s. The appearance of new materials plus advances in the design and construction of helmets have been accelerating, especially since 2001.
What is amazing about this is that modern combat helmets first appeared in 1915 during World War I (1914-18). Initially there were several types. The U.S. adopted the .6 kg (1.3 pound) flat British design steel model and used it for 25 years. This was replaced by the 1.3 kg (2.9 pound) M1 helmet in the early 1940s. This was the “steel pot” and liner system that lasted over four decades. The 1.5 kg (3.5 pound) PASGT (Personnel Armor System for Ground Troops) replaced the M1 in the early 1980s and lasted twenty years. The ACH replaced PASGT by 2007 but by 2012 the ECH (Enhanced Combat Helmet) began appearing as a replacement for some ACH models. ECH, like ACH is built to take lots of accessories and is the version bought by police and emergency service organizations.
The Kevlar PASGT design was a third generation combat helmet, nicknamed the "Fritz" after its resemblance to the German helmets used in both World Wars. That German World War I design, which was based on an analysis of where troops were being hit by fragments and bullets in combat, was the most successful combat helmet in both world wars. This basic design was finally adopted by most other nations after the American PASGT helmet appeared in the 1980s. Most of the second generation helmets, which appeared largely during World War II, were similar to the old American M1 design. The fourth generation helmets, currently in service, use better synthetic materials and more comfortable design. Now they are often lighter as well. If you carry this stuff up to 18 hours a day in a tropical climate lighter is much better.