I'll leave it to experts to comment on the holey rock, but I'm having some trouble with scale/size. In one shot I assume it's on a table with the ground a few feet beneath it but it makes the rock look huge. What are the approximate dimensions?
I don't think anyone would put that in a canoe , way too big. maybe an attempt at making a mill stone ?
or maybe the pic is not showing the proper scale like mentioned above.
Modern bullet & need measurements to I.D. That may be an anchor. Can you give us an approximate size && weight ? Need pix on both sides on the stone as well.
I think your stone is a natural trace fossil. There seems to be a second hole that appears too smooth to be chiseled or "hammerred" in place. The hole in a stone anchor is always funnel shaped on either side.
Can you put something of known size in an image with it?
Agree with CaptEstaban & Pistol Pete that the bullet is a modern .30 cal(+/-) full-metal jacket.