i took my 5 quarter collapseble canteen bladder from it's cover to check the condition of the bladder and discoverd that the bladder is bigger than the cover ( a small part is folded ). does anyone know were it's for ? or is it just a production error ?

I just dismatled mine and found no fold. It is likely just a production error. If you can get 5 qts in it should be no problem. Spare bladders are available from Brigade Quartermaster's over here in the USA.

thanks chris

Believe it or not the one with the folded section is the right on e and the one that fits exactly is the defective one.Having the bladder bigger than the holder insures that the forces and stresses are tranfered to the holder, so they work together to resist bursting.The ones with the unfolded bladder failed the army's drop test. Hope that helps

So, Now I have a canteen I cannot drop LOL

At least not from a low flying chopper, that was the original design spec. Not sure if it makes any difference to us. The best source of info. on them is , " Jungle Snafus...and Remedies," by the designer Cresson Kearny of," Nuclear War Survival Skills," fame. Hope that helps