Quite a few links across the country. Go to any gun shop that's been around for a while and ask the owner about what they used to sell during the Clinton Gun Grab of the 90's. If you don't have one nearby, try Tony's Gun's & Police Supplies in Sumter SC. Tony kept a pretty good supply of the Sissy15's in his shop.

https://www.bing.com/ck/a?!&&p=ed8b97...&ntb=1