This is very old info, about 20 years, but I taught with a guy who’d served two hitches as an Lt in 2nd Rangers. He’d regale me with stories about where he’d been and what he’d done. I asked him once about the M14. He loved the weapon and told me that they were being reserved for future use where their positive attributes, long range and that Garand action that fires in peanut butter, would be useful. He specifically mentioned desert and mountain environments. That was 20+ yrs ago so who knows now.
The troops carry a lot of useless weight, what ever happened to Solder Selection, the average load of an Infantry man for at least the last 2000 years has been 60 pounds.