Hey, I have a serious question regarding pin rigs.

I often see disclaimers and warnings from manufacturers and experienced jumpers about having too tight a pin tension on pin rigs. My question is:

why?

I admit my sole pin experience is with skydiving rigs. As a rigger and experienced skydiver, I know for a fact that the adage that "if you can close it with your hands without assistance, and if your PC is in good shape, the container WILL open" is 100% true. Ignoring misrouted bridles of course.

Of course I understand that we are talking about subterminal versus terminal. However, I have a hard time seeing how after a 1-2 second delay a 42" PC is not going to pull the pins on a pin rig, following the same adage. The old test for determining if your skydiving rig was tight enough was to put the rig on the floor, pull on the bridle, and if the rig stated to lift off the floor a bit before the pin pulled, you were good to go. Assuming your average skydiving rigged weighed about 22 lbs (sheer guestimate), that equates to a pull force of about 22 lbs. Are we saying that after a 1-2 second delay 42" is not giving us 22lb of pull force?

It seems that if 42" will pull brand spankin new velcro in a head down shrivel flap situation without too much trouble, it would easily deal with a pin in any situation.

I guess I am asking because I would feel pretty nervous taking a pin rig off some off an object with some of the pin tensions I have seen in the field, and discussed on the board, especially terminal. It seems like at 4 to 6lbs pull force, the only thing standing between you and a nasty horseshoe mess is the pin flap. I would guess that the designers did not intend the flap to take such an important role in keeping the pins in place....

So..... what am I missing?


Standard Disclaimer:
Now before I get a bunch of flamage, please understand I am asking for purposes of enlightenment, not to stir up crap or call the 4-6 pounders stupid. I fully understand that these guidelines are based on experience and best practices, so please let me know why the pin tensions are supposed to be so low....