This interesting photo is from the Osprey publication, “Armies of the Vietnam War 1962-1975”.
Caption for the photo reads:
Soldiers of the 196th Light Inf.Bde., Americal Div., examine a VC cache near Chu Lai in December 1970. The abbreviated rifleman's equipment is typical of short-range operations at this period. Bandoliers are used to carry both magazines and grenades, and spare M-60 belt is looped around the riflemen's waists. The two XM203 grenadiers at the right wear the special grenadier's ammo vest; the man at far right also carries his rifle magazines in a spare canteen carrier, and ration toilet paper packs in his helmet band. Third from right has a Kabar knife sheathed in his trouser cargo pocket, and fourth from right has a civilian hunting knife on his belt.
A lot going on in that photo. The bandoliers used to replace, rather than supplement, the issue “ammo case” [pouch] are of particular note.
A previous blogpost discussed stripper clips or chargers. In this photo the bandoliers are being used to carry grenades and 20-round magazines.
More recent examples of bandolier can also accommodate 30-round magazines. In the photo below, a light-coloured thread is visible. Removing the thread makes each pouch deep enough to carry a 30-round magazine rather than a pair of stripper clips.
If you shoot 7.62 x 51mm (or 6.5mm Creedmore) you needn’t feel left out. Below is an Australian bandolier intended for use with the SLR/FAL.