GOlly - it is almost like I made a manual for the S5 once:
What feedneck threading is my marker?
CCM uses their own threads for the feedneck on the S6 and S5B. However, on older Series 5 markers they used two different threads. The first Series 5’s were made to take Angel threaded feednecks. Later S5’s were made with CCM threads akin to the S5B and S6. You know you have one of these later S5’s if your serial number ends in ‘A’. If you just have numbers – it is angel threaded.
Check the stickies...