PLA Type 56 85 mm Gun, where and when.

 Came across two old PLA propaganda photos, decided to do some forensic anthropology to see when and where those two were taken

Clue #1: The Type 56 (No, the other Type 56):

the Type 56 85 mm anti‑tank gun, China’s clone of the Soviet D‑44 divisional gun. Factory 247 started cranking these out in 1956, eventually producing over 11,000 of them. For decades, every PLA infantry division had a full battalion of these things (18 guns per division), and they saw action everywhere (link):

• 1958 Kinmen artillery duels
• 1969 Sino‑Soviet border clashes
• 1979 Sino‑Vietnam War
• And basically every border skirmish with Vietnam afterward

Clue #2: The GK80 steel helmets:

These helmets were rushed into production for the 1979 Sino‑Vietnam War, but they didn’t become common until the early 1980s. By then, border defense units and infantry regiments in Yunnan and Guangxi were wearing them like it was the new summer fashion line (link)

So: post‑1979, likely early 1980s.

Clue #3: No leggings — a big clue:

The troops in the photos aren’t wearing the traditional PLA puttees (绑腿). These leg wraps have a 2,000‑year history — Qin Dynasty terracotta soldiers wore them, Korean War troops wore them, and 1979 Sino‑Vietnam War infantry definitely wore them (link).  Photos of them can be found all over the internet 

The practice only died out when the PLA rolled out the Type 85 and Type 87 uniform series.
So: mid‑1980s or later.

Clue #4: Type 56‑1 under‑folder rifles:

The so‑called “Type 56 submachine gun” (yes, that’s what PLA called it) — the milled‑receiver, under‑folding stock variant. Before and during the 1979 war, squad leaders carried these while the rank‑and‑file lugged the other SKS based Type56s.

But in these photos? Most of them got one. That’s a big hint:
By the early–mid 1980s, Type 56‑1s were widely issued in border units, especially in Yunnan and Guangxi.

Clue #5: Summer uniforms + towing an 85 mm gun uphill:

Nothing says “PLA border defense in the 1980s” like a bunch of conscripts in summer cotton uniforms towing a 1.7‑ton artillery piece up a slope.

(Yes, towing. Get it? Tow‑ing a Type 56. I’ll see myself out.)

Put all the clues together – These photos were almost certainly taken in the mid‑1980s near the Sino‑Vietnam border.