Fwiw, I disliked the M16, i.e., "The Mattel Special", so much that I "issued myself" a Model 37 Ithaca pump-shotgun in lieu of a rifle in BRD.
(At the range where I was ever likely to have to fire a shot in anger, I never felt that I was "under-gunned", there.)
Otoh, when I was "seconded to an international organization" & where our team-members were allowed by COL Santiago de Vega to carry any forearms that we had "in stock", I carried a USN-type NM Garand in 7.62NATO & a pair of BHP, that had been "seized from a narcotrafficante".
(I also had a Spanish-made double-barreled 12-gauge shotgun, too.)
For some odd reason or other, we had "acquired" a HUGE quantity of Lake City ammo in both M2 Ball and 7.62x51mm. The armory also had numerous cases of Spanish-made 7x57mm ball ammo, too.
Handgun ammo was 9x19mm & .45ACP, from Argentina.
Note: One member of our team, who was the equivalent of a US SFC/E7 from a Central American nation, by personal choice, armed himself with a FN-made BAR. = "Arturo" was about 74" tall & 270 pounds.