Aside

A standard, everyday, FAL is 10.9 lb. loaded.  No optics, no lasers, no suppressor.

With a 100 round basic load it's 17.3 lb.

The, strangely, beloved M14 is the same.

If we upped the spare magazine count from four to six, like the M7, we get 140 rounds and that increases the load to 20.5 lb.

0.7 lb. lighter than the M7 with it's basic load and without the capabilities of the optics, lasers and suppressor.

The thing is, it was nearly universally agreed that the 7.62 battle rifles were too heavy and you got insufficient dakka.

The "amusing" thing is we could add a 5.56 calibrated M157 optic to a suppressed M4A1+ and have a loadout of 17.1 lb.  Saves 4.2 lb. and has 50% more shots.  We'd be sacrificing the theoretical benefit of the 6.8x51mm round.

If only someone had written a book 76 years ago explaining how piling on pound after pound on the troops was a bad plan...

Remember, the folks lugging an FAL or M14 around weren't also encumbered with body armor past a steel helmet.