4V50Gary - the 686-4+ was made for one year, 1997 IIRC. There were four barrel lengths done, 2.5", 3", 4" and 6". The 686-4+ was the last of the 686's with forged parts and hammer mounted firing pin.
The 686-5+ implemented the frame mounted firing pin and MIM parts. Hope this helps!
The 686-5+ implemented the frame mounted firing pin and MIM parts. Hope this helps!