"Wear and tear" and "proper care" don't always go together. A good example would be ex-police guns, which were carried a lot, can have lots of holster wear and even rust, but which are like new inside. They are great buys for people who want shooting guns, not collecting guns.
On the other hand, some guns look very nice on the surface, but have serious problems inside due to amateur gunsmithing efforts or poor quality to begin with.
Some tips, most of which are obvious:
Remove the magazine and make sure the gun is unloaded. Note any problems in magazine removal and in retracting the slide. Note any unusual scratches or marks on the magazine, indicating it was fooled with. That indicates some kind of feeding problems.
Check the disconnector by operating the slide with the trigger pulled. The hammer should cock and stay cocked, unless the pistol is DAO.
With slide retracted, check the barrel with a bore light for any pitting or excessive wear.
Release the slide and note any problems in going into battery.
Check the trigger pull. A very light pull is NOT a good sign, nor is any tendency of the hammer to fall when the slide is released. (Yes, I know, but dropping the slide when testing a gun is OK IMHO.)
Check all safeties and make sure they work properly. If the gun is supposed to have, say, a magazine safety, make sure it is present and works. Even if you are planning to remove it, if it is not there what else has been done to the gun?
Replace the empty magazine and retract the slide; check the slide stop (if one is present) to make sure it works.
Check screws and pins. Signs of burred screw heads or punch marks around pins indicate amateur disassembly work, and could be signs of trouble. And they hurt collector value, of course.
Check slide-frame fit and slide-barrel fit by wiggling the slide on the frame and the barrel in the slide. Some small play is normal except on very tight target guns, but it should not be excessive.
All of this can be done without disassembling the pistol and takes maybe a minute, a bit more if using the bore light. It will catch 95%+ of the possible problems.
Jim
