Ok, Lock puller.
Most automobile locks are three parts. Lock cyl, Cyl housing, and tailpiece. A puller will force the plug out of the housing destroying the facecap(shiny piece you see) and most likely the housing. after it is out you have to get hold of the tail piece and move it to trigger the lock.
Is quicker to unlock a car with conventional locksmith tools
since they do not require reapiring the lock and for the most part quicker.
Pick-Gun. Yes they work on pin tumbler locks, but not wafer locks(most cars, desk locks and so on)I use one quite a bit myself. But like normal picks they take practice and the correct amount of tension to work.
Lock impressioning
This is what you are refering to when the locksmith sticks a key blank into the lock and wiggles it then files.
The pins in the lock do not meet the shear line to turn with a blank key.These pins will leave a mark on the blank if it is not lined up. The locksmith is filing the mark down until it quit marking. When all pins are done the key will turn.
The keyblanks used are brass and filing them smooth or with a knife edge on the helps the pins mark it better. Most locks on automobiles only have 4 or 5 depths. 1 depth being a no-cut. a 4 or 5 (depending on the vehicle) is all the way to thru the blade. After enough time and practice it is not hard to figure out approximately how far to file the key each time it marks. I average 15 minutes on most nissans makeing keys this way. Old fords are also easy to do this to. Some hondas and toyota go real well. GM and Newer Fords are quite hard to impression, and there are easyer ways to produce a key.