Second Chance (of Bullet resistent vest fame) used to make and sell their Thunderzap ammuntion which used a plastic/polymer/nylon/whatever bullet.

I may have an old American Handgunner magazine around here with an advertisement for them, I'll check.

IIRC they stopped making them and we used the remaining stock up shooting the Subway event at the Second Chance match and it was 5 pins at 25 feet with 6 shots, just tip them over not take them off the table as was standard, using Snubnose 38s with the Thunderzaps.