I've been messing around with picklocking for about a month. I know all the basic theory (security pins, shearn line and stuff). I can easyli pick a masterlock No. 5 and a No. 3 .
But, these are the only 2 lock that I can pick

So here comes my question.
- What's the next step after beating those 2 master lock. do you have a suggestion on one a bit harder, but not that hard too...
-Is there a way (looking a the key, how the way the lock act etc) to know if the lock has security pins or not?
-Do you have any tips on how to beat those security pins?
-Why with only certain type of lock, I can't feel the pins... I know I need more experience, but sometimes I feel them and some other times I don't
-Finally , do you have more information on the little keyhole behind a master combination lock? I can't pick this one !

Well Thanks a lot for you answer in advance, hopefully you'll be able to help me

cheer