Can any members advise what this back pack was used for?

[browningautorifle]

I'm still thinking some sort of ammunition carrier/pack? A bit like the US M1 ammo bag, only capable of being carried on the back.

GP M1 Ammunition Bag by Combat Serviceable

Is anyone able to confirm that ammunition is never carried on one's back, please?

Reference that whole thing...I carried belts in different places but it wasn't very useful to have belts in your ruck on your back. You just have to understand how quickly the weight builds up. The bag you show was carried at the hip or across the belly of the US troop, sometimes Thompson mags or grenades. The other was called the "Musette" bag and is referred to also in that sales pitch, looks like a small pack. We honestly tried to keep our belts in boxes to keep them clean and fit for use as much as possible.

Sad thing about this little bag is I remember seeing them when I was young and there was lots of stuff held over from the old days but never knew what it was for, nor did anyone else. I'm sure it was in communication gear stores it had been sitting, the steel pegs on the bottom are unmistakable. A soup urn, yes, I'd believe that. Never saw them used though, by then we had the US issue thermos boxes.