tapered upper pins

[zekeo]

I'm sure this is somewhere on here, but I was disassembling a master-keyed, construction keyed yale lock (no way I can get it all back together) and noted that the upper pins are tapered in almost a half-spool configuration. The springs sit around instead of above these pins. I was just wondering whether these added any pick-resistance or if they are just another style of setting up pin stacks. If so, is there any other benefits to this kind of upper pin?

By the way, I was playing around with the guts of this lock and it sure seems with the master and construction keying that they're almost absurdly easy to pick, and not only that I could easily figure out the biting of the master key. (This was an extra lock that the construction guys left me on my new apartment). Is there any conceivable master key system in which the master can't be determined from one lock?

[fixer]

Is there any conceivable master key system in which the master can't be determined from one lock?

Not unless you go to an electronic system. The master key for any physical system can be determined from one lock, indeed, you don't even need to take the lock apart to do it

[zekeo]

So anyone have any ideas on these tapered pins?