Chorwon Museum Part 2
The description given is "60mm" and "81mm" so these can only be mortar projectiles. I'm not sure about the two items on the right.
M 59 155mm piece. This is a "Long Tom" gun used for direct fire. Most pieces during the war were howitzers capable of direct or indirect fire, indirect being lobbing shells at a high angle like a mortar, a useful feature in mountainous terrain.
F 86F