A coaxial connector assembly comprising: a housing having a mating end and an oppositely facing contact assembly receiving end , the housing having at least one contact receiving cavity which extends from the mating end to the contact assembly receiving end , the contact receiving cavity having a mounting section proximate the contact assembly receiving end ; a contact assembly positioned in the contact receiving cavity , the contact assembly having a shell and a center contact , a retainer portion coupled to the shell and positioned proximate the mounting section of the contact receiving cavity , the contact assembly having a front flange proximate a mating portion of the contact assembly ; a positioning member inserted on the mating portion of the contact assembly , the positioning member comprising a ring with an opening provided in its center, an outer diameter (D5) of the ring being smaller than a diameter (D1) of the contact receiving cavity but greater than a diameter (D3) of the front flange , an inner diameter of the opening being equal to a diameter of the mating portion of the contact assembly , the positioning member cooperating with the flange to position the positioning member on the mating portion of the contact assembly ; characterized in that the positioning member has a slot which extends from the opening through the ring to an outside circumference of the ring to allow the positioning member to be resiliently retained on the mating portion of the contact assembly and in that the positioning member cooperates with a wall of the contact receiving cavity to limit the movement of the mating portion of the contact assembly in a direction which is transverse to a longitudinal axis of the contact assembly and reduce sag. a housing having a mating end and an oppositely facing contact assembly receiving end , the housing having at least one contact receiving cavity which extends from the mating end to the contact assembly receiving end , the contact receiving cavity having a mounting section proximate the contact assembly receiving end ; a contact assembly positioned in the contact receiving cavity , the contact assembly having a shell and a center contact , a retainer portion coupled to the shell and positioned proximate the mounting section of the contact receiving cavity , the contact assembly having a front flange proximate a mating portion of the contact assembly ; a positioning member inserted on the mating portion of the contact assembly , the positioning member comprising a ring with an opening provided in its center, an outer diameter (D5) of the ring being smaller than a diameter (D1) of the contact receiving cavity but greater than a diameter (D3) of the front flange , an inner diameter of the opening being equal to a diameter of the mating portion of the contact assembly , the positioning member cooperating with the flange to position the positioning member on the mating portion of the contact assembly ; characterized in that the positioning member has a slot which extends from the opening through the ring to an outside circumference of the ring to allow the positioning member to be resiliently retained on the mating portion of the contact assembly and in that the positioning member cooperates with a wall of the contact receiving cavity to limit the movement of the mating portion of the contact assembly in a direction which is transverse to a longitudinal axis of the contact assembly and reduce sag. the positioning member has a slot which extends from the opening through the ring to an outside circumference of the ring to allow the positioning member to be resiliently retained on the mating portion of the contact assembly and in that the positioning member cooperates with a wall of the contact receiving cavity to limit the movement of the mating portion of the contact assembly in a direction which is transverse to a longitudinal axis of the contact assembly and reduce sag. <EOS>