Q: Is the locking mechanism on these pliers spring loaded?
Yes, these are spring loaded and they will pop back.
Q: Do these 6 safety wire pliers have a spring return? (automatic)?
Im actually looking for this same safety wire pliers, WITHOUT the automatica return. I had a pair from about 25 years ago, but they were stolen.
The one I had looked just like this one, and didnt have the spring return, and when you pulled to twist, you simply pushed in on the shaft and the end knob rotated on a bearing instead of twisting/digging into your hand.
No, the twisters in this kit have a manual return.