Firstly, try and take clear photographs in future. It will greatly help in IDing finds.
Secondly, be very VERY careful in this and many other areas as the act of recovering relics, regardless as to whether or not you dig for them, is against the law as the relics are now classed as property of the state. Even a small bit of bent and broken cartridge case will get you a fine. More will get you a bigger fine and even imprisonment.
Now, on to the pictures. The ammo boxes look like 25lber boxes as WW2hunter has pointed out. The hole shown in the picture is obviously where one or two of the crates have come from. The bullet heads are likely to be 20mm rounds of WW2 vintage and are extremely dangerous. Just looking at them puts them in a bad mood !
Be careful out there......relic hunting is not for the faint hearted, or for the clumsy and/or idiotic ! The simple rule is, if you don't know what it is, don't touch it.