The IDF uses rubber bullets extensively as a non-lethal form of ammunition. I think during the Nth intifada there was a story about plastic bullets being used, with them being actually worse than metal since they wouldn't show up on x-ray, although they would shed energy and momentum really fast compared to metal.

http://www.nytimes.com/1988/09/29/world/us-protesting-israel...

http://www.nytimes.com/1989/01/29/world/israeli-army-lawyer-...