Melt candy bars and condensed milk in a heatproof bowl set over a saucepan of simmering water, stirring, until smooth. Do not allow the bowl to touch the water. Remove the bowl from the saucepan and whisk in the milk, half and half, and chocolate syrup. Refrigerate until cold, at least 2 hours,.
Churnin ice cream make according to manufacturer's instructions. Transfer to airtight container and freeze until firm, at least 2 hours.