I only know that during World War II, the United States Marine Corps had 12 men, 10 Garland 8 semi-automatic rifles, 1 Babbrowning, a Springfield sniper rifle, officers with pistols, and some had 1 or 2 Thomson instead of Garland. It seems that whoever holds what weapon has nothing to do with rank, but I think it should be related to physical fitness and proficiency in using it. Some people can only shoot one shot, while others can better control the repeating weapons, which is related to personal talent.

And commanders (even squad leaders and company commanders) are generally relatively backward. If Thomson's short-range suppression weapon is in the rear, it is obviously useless.

In addition, it is inevitable that weapons are damaged or ammunition is insufficient on the battlefield, so it is not surprising that the configuration is chaotic.