It's the shape and weight that will make the difference. What's the diameter of the balls? Might not work in a wobbler/vibrating tumbler and I'd guess it won't polish the brass but leave a matte finish. Smaller pins will get into small areas and the ID of the case (some folks like that?) and the small diameter and blunt ends will also have an effect on the finish (less "impact" on the brass).

Won't hurt anything to give it a try, what kind of tumbler do you use?