Thanks guys,
I would think NEW coins are uniform in weight, but yes, circulated coins will wear and reduce the weight. I've tried bullets, but they vary in weight according to the alloy.
One of the reasons I ask these kind of questions is where I live; Lost Angeles, Mexifornia. It is difficult to get gun supplies like powder, bullets, reloading equip., etc. Almost all my purchases are made via the web. I looked for powder for about three weeks and found only 3 places to purchase it (I refuse to pay "Hazmat" and extra "Handling" fees to buy powder on line). Two with a very limited selection (took me a couple months to find some Unique) and one 1 1/2 hrs. drive away. I haven't seen any reloading equipment at the places I've found, and the chain "sporting goods" stores mostly sell shoes. So, instead of waiting for a web order to ship I look for acceptable replacements; coins for check weights, and hobby rock tumblers and Lizard Bedding for cleaning my brass. It's kinda fun too.
BTW, there hasn't been a Gun Show in L.A. County in many years.