Bullets shouldn't be magnetic since they are made of brass, copper and lead, but I guess these ones had enough rusty ferrous material stuck to them that I pulled them out with a magnet anyway.
The little rod below the horseshoe is also entirely made of copper and not all magnetic, but it was held on to the magnet by some rusty scrap.
I also got a fair amount of loose change, and what I think is a door knob that I was a little worried could be a grenade when I pulled it out amongst the bullets.
I'm sure I have one of those folding knifes, the better condition one. I'll have to find it tomorrow.
Edit: found it. Looks identical. I bought it from a military surplus shop around 2004/2005.