The term “Grunt” was probably coined by a GI with first hand experience.
For lightness with strength, go to the pro bicycle industry. Cycling enthusiasts shave grams (28 grams = 1 ounce) off their equipment, whether it’s worn or on the bike, because they are all the horsepower they have (lowering weight = raising power).
Titanium and carbon fiber are the two main materials that do the job. They aren’t as expensive as they used to be. When the Soviet Union collapsed, much titanium flooded the market and drastically reduced its cost. Manufacturing a lot with carbon fiber has expanded enough to bring down the cost.