Just wondering if you have seen the different versions of the rucksacks? When I was in the service I had a very simple version of the LK35. The fabric was thin so we all put in a plastic bag to make it waterproof. I´ve seen version with the straps on the lid in a different color. Another version is with a coating only on the inside of the lid. The latest version is made in cordura and had a coating inside (all over). The version of the 70LK I´ve got is made in Norway by "Bergans" in the year 1987. The early models had the straps (placed over the side pockets) in leather. The straps was used to secure tools or skis. My version has straps i syntetics but the pair of straps on top and the ones securing the lid and waistbelt is in leather. The small one was used by the ordinary infantry man & the bigger was used by the rangers (marines, paras etc). The LK35 carry what you need in at least 24 h. The rangers needed a bigger rucksack for a longer time in the woods. The manuals written by the army says that it is possible to carry equipment between the frame and the sack of the 35LK (not recommended doing this with the 70LK). By slacking the straps connecting the pack to the frame makes this possible. I´ve seen pics of a 35LK packed with a PRC-77 (the radio used by the US in the Vietnam war), 2 extra sets of batterys, extra underwear, warm sweater, warm coat, rations for 2-3 days, stove (complete), thermos, 1.5 liters of water, one-man-tent (basha), saw, shovel, sleepingmattres, some tools (nails etc) & sleeping bag on top. The radio was between the frame and the pack standing on the small shelf. I can imagine it was quite heavy... /Swede 
