Oh, this is good. An excuse to open the safe. I had to find out, since I had the usual plugs and muffs on at the range.
And the answer is...please wait, loading...1-7 no rattle, 8 rattles, 9 doesn't, 10 rattles, 11 doesn't, 12 rattles, 13 doesn't, 14 rattles, and 15 doesn't. Odd numbers are good!
Good question! John