Thanks for all the great ideas!!! Sorry for the late "thank you" but I've been away.

I think I'm going to hit up Gander Mountain or Bass Pro and try the bags of lead shot. I'm looking at adding @50 lbs so I think that might be the easiest way to go. I've bought bags before to use in my shaping bag and I remember it being heavy and cheap.

I'll let you know how it works out.