This is probably even a cheaper way to go. It gives me an excuse to buy more mags anyway. Thanks!Seriously though- yeah, why spend more on a rubber dummy than you would on a 10rd factory mag and a couple snap caps? If weight is the issue you could probably take out the mag spring and put a baggie full of sand or something in there instead. Paint the bottom bright orange so you don't get it mixed up with a real one some day and shoot a hole in your bathroom mirror, and you're good to go.