I tried to keep the original question brief. I can go into a little more detail. Firstly, there is no rig, in my opinion, that has better R&D then Vector. It's been my personal rig for 15 years. If I still have concerns about this situation, I'll give Bill Booth a call. Who ever said it doesn't get any better then that was right.
The rig belonged to me, but was a loaner at my DZ. It was a vector 2 with the a meshless, stainless steel pilotchute. The jumper had an extremely low pull and landed without incident under the main. As he was walking back to the hanger the reserve flaps opened and the pilotchute dropped out. The reserve container had stayed shut through landing and about 100 feet of walking.
We inspected the rig and found the expert cypres had fired and cut the closing loop. We checked the spring, it passed (although I don't recall the number). Since the flaps had opened we were unable to inspect the closing of the packjob. Everything else seemed in order. We confirmed a cypres closing loop.
I don't know if a firing at terminal would have significantly changed the dynamics. Given that the reserve container never opened, even through flight and landing, I doubt it.
I was on the DZ and observed the incident.
Any ideas?