I took mine to the beach and used good old sand. I've seen guys use everything from flour to birdseed to plastic bb's like you shoot in airsoft guns (didn't like that bag at all) If you are going to be carrying the bag in the field - like you might do shooting squirrels, it might pay to have something light. Mine is heavy, but I like it that way - very solid and I don't carry it very far.
Putting a scope on is not very difficult. I prefer Warne rings and bases and I think you would find they are easier to install perfectly than leupold where sometimes it's difficult to get the rings perfectly alligned with each other. I have a one inch diameter bar of stainless steel which makes this easy. Warne are the same price as leupold and highly regarded.
