An injection molding apparatus comprising an injection molding machine , a manifold that receives injection fluid from the machine and routes the injection fluid during the course of an injection cycle from an upstream end toward a downstream end of a fluid flow channel disposed in a nozzle communicating with the manifold , the fluid flow channel having a flow axis (AX) and a channel length, the fluid flow channel communicating at the downstream end with a gate to a cavity of a mold, the apparatus including: a valve pin driven by an actuator , the valve pin extending axially through at least a portion of the channel length of the fluid flow channel , the valve pin having an upstream end interconnected to the actuator and a downstream end , the valve pin being drivable by the actuator axially upstream and downstream through the fluid flow channel, the fluid flow channel of the nozzle including a throat (T) having an inner circumferential surface ((TS) having a selected throat configuration and throat diameter (TD), the valve pin having bulbous portion (B) having an outer circumferential surface (OBS) and a bulb diameter (BD) adapted to interface with the inner circumferential surface (TS) of the throat (T) of the nozzle to enable a restricted degree of volume or velocity of flow of injection fluid relative to a maximum degree of volume or velocity of flow when the bulbous portion (B) of the valve pin is axially aligned (AL) with the throat (T), the valve pin 40 being adapted to be disposed in a start of cycle or upstream flow restriction position such that a flow restriction gap (G) is formed between the outer circumferential surface (OBS) of the bulbous protrusion (B) and the inner circumferential surface (TS) of the throat (T) that is large enough to enable a predetermined small amount of flow of injection fluid through the gate that reduces a difference in fluid pressure between an upstream interior volume (UIFP) of the channel and a downstream interior volume (DIFP) of the channel 45b, the valve pin being drivable to a maximum downstream position where a distal tip end of the valve pin closes the gate and stops flow of the injection fluid through the gate . a valve pin driven by an actuator , the valve pin extending axially through at least a portion of the channel length of the fluid flow channel , the valve pin having an upstream end interconnected to the actuator and a downstream end , the valve pin being drivable by the actuator axially upstream and downstream through the fluid flow channel, the fluid flow channel of the nozzle including a throat (T) having an inner circumferential surface ((TS) having a selected throat configuration and throat diameter (TD), the valve pin having bulbous portion (B) having an outer circumferential surface (OBS) and a bulb diameter (BD) adapted to interface with the inner circumferential surface (TS) of the throat (T) of the nozzle to enable a restricted degree of volume or velocity of flow of injection fluid relative to a maximum degree of volume or velocity of flow when the bulbous portion (B) of the valve pin is axially aligned (AL) with the throat (T), the valve pin 40 being adapted to be disposed in a start of cycle or upstream flow restriction position such that a flow restriction gap (G) is formed between the outer circumferential surface (OBS) of the bulbous protrusion (B) and the inner circumferential surface (TS) of the throat (T) that is large enough to enable a predetermined small amount of flow of injection fluid through the gate that reduces a difference in fluid pressure between an upstream interior volume (UIFP) of the channel and a downstream interior volume (DIFP) of the channel 45b, the valve pin being drivable to a maximum downstream position where a distal tip end of the valve pin closes the gate and stops flow of the injection fluid through the gate . <EOS>