1943 Varied Rucksack???

Picked up the metal rifle clip for it on Monday at a flea market. Guy had a beat up rucksack for sale that had the clip. Offered him $5 for the clip and he accepted. Ordered the upper strap yesterday also so it will be complete in a few days.

Strap came today and I must say, at first appearances this has to be a pretty stupid idea. I must be missing something and this will require an experiment. The hook that holds the ring on the rifle strap is upside down and it falls out of it. I suspect with the rifle in place something holds this in place adequately or the rifle would wind up muzzle first into the ground. There is a rather large grasping tab to pull it out of the hook so there must be pressure from above to keep it in place.

So now I have to A) find my SVT 40 bayonet for that experiment and B) find my Garand for this experiment. I do at least know where the Garand is, just not sure how deeply it is buried in the safe.