Injection molding apparatus comprising: a hot melt distribution block, a hot melt discharge nozzle secured to said block, said nozzle having a base end configured to permit the nozzle to swivel with respect to the block, said nozzle further having a discharge end comprising a nozzle tip, a mold having a pair of opposed mold halves (38, 40) that cooperatively define, when the mold is closed, a cavity and a gate passage leading to the cavity, at least one of said mold halves (38, 40) being movable away from the other mold half to open the mold along a split line that longitudinally bisects the gate passage and the cavity, and a tubular insert mounted on one of said mold halves (38, 40) and having an insert tip projecting into the gate passage in sealing engagement with sidewalls thereof, said insert having a chamber disposed to receive the nozzle for delivery of hot melt from the nozzle tip into the cavity through the insert tip, said chamber having an end wall surrounding an opening into said insert tip, said chamber further having an axially extending locating sidewall at the radially outer limit of said end wall, said nozzle tip having an end face and an outer edge confined radially by said locating sidewall of the chamber for locating the nozzle tip in axial alignment with said opening and permitting the nozzle tip to swivel relative to the insert during swiveling of the nozzle relative to the block, whereby said insert has a lower thermal conductivity than said nozzle and said mold, characterized in that said end face of the nozzle tip is spaced away from said end wall of the chamber to define a void. a hot melt distribution block, a hot melt discharge nozzle secured to said block, said nozzle having a base end configured to permit the nozzle to swivel with respect to the block, said nozzle further having a discharge end comprising a nozzle tip, a mold having a pair of opposed mold halves (38, 40) that cooperatively define, when the mold is closed, a cavity and a gate passage leading to the cavity, at least one of said mold halves (38, 40) being movable away from the other mold half to open the mold along a split line that longitudinally bisects the gate passage and the cavity, and a tubular insert mounted on one of said mold halves (38, 40) and having an insert tip projecting into the gate passage in sealing engagement with sidewalls thereof, said insert having a chamber disposed to receive the nozzle for delivery of hot melt from the nozzle tip into the cavity through the insert tip, said chamber having an end wall surrounding an opening into said insert tip, said chamber further having an axially extending locating sidewall at the radially outer limit of said end wall, said nozzle tip having an end face and an outer edge confined radially by said locating sidewall of the chamber for locating the nozzle tip in axial alignment with said opening and permitting the nozzle tip to swivel relative to the insert during swiveling of the nozzle relative to the block, whereby said insert has a lower thermal conductivity than said nozzle and said mold, characterized in that said end face of the nozzle tip is spaced away from said end wall of the chamber to define a void.