Any Cal, I tend to agree with your take on this. I still have not seen convincing evidence to convince me that spring rate has much to do with lockup under pressure.
MarineHawk, the BB 10mm auto loads I tested had a tight SD on velocity with a spread of 25 fps. Consistent stuff. This was a 180 @ 1335 average from a 4.6" barrel. Pretty solid ammo. Too bad they load that crappy Montana Gold bullet now though.