One of the chalenges faced when picking locks is how to deal with spool pins or mushroom pins. The spool pin is designed to make the lock barrel bind as it is being picked. The binding makes it very hard to continue picking the lock pin by pin unless you know how to deal with the spool pins.
The best trick to deal with the spool pins is to try to pick the lock as normal, pin by pin then feel for the large turn in the barrel. If the barrel turns quite a lot then that is an indication of spool pins being present and being in the active binding position.
The good news is that when the spool pins are binding the pins with standard top pins have been placed in the correct positions. There are now only the spool pins stopping the lock from being picked.
When a spool pin is pushed down it force the pin to straighten up in the chamber. To straighten the lock plug must rotate back to be straight with the top pin chamber. You will see and feel the plug rotate when the spool pin is pushed. Using light steady tention the spool pins are pushed into position.
Lock picking spool pins is not always this easy. Often as the spool pin is pushed to position it will cause other pins to jump out of position. While this can be frustrating there is a technique I use to overcome this the majority of the time. It is simply to try to put diagonal pressure on the plug with the tension wrench. Try to force the barrel to turn from one side or the other, not straight. This will make it easier to pick in a straight line from either the front or back.
Info on spool lock picking thanks to some locksmiths in Australia.