OK, so the Arms & Armor supplement says that a sack of 20 sling bullets weighs .5 lbs I am thinking this is a little light since they are 3 inch long lead bullets. The D20 SRD says that 10 bullets are 5 lbs, which I think is *way* too heavy, especially for something that gets destroyed on impact.
I have even geeked out and looked at modern Daisy Slingshot Steel (zinc coated) Ammo, and 20 of the 1/4in ball-bearing type weigh .3 lbs!
I know I am over-thinking this, but how do you guys deal with them?
EDIT: More geeky-ness: The interwebs says that a piece of steel is 68% of the weight of same sized piece of lead. So, by my sh!tty math skills that means that twenty 3-inch-long lead bullets should weigh closer to 5 lbs, and I am thinking the decimal is a typo. I know I am over-thinking this, but it's stuff like this that floats my boat sometimes.