DON'T BUY A TAURUS REVOLVER. I've sent so many of those things back to Miami, I can't count them any more.
The Smith 686 is a great gun with the 4" barrel. The Ruger GP - 100 is just as strong, reliable, solid, and accurate, and costs about $100 less. The comfortable Hogue grip on the Smith and Wesson is a $25 part for the Ruger and it installs in five minutes.
If money is really a concern, you did not email me so now I will pontificate on the purchase of used revolvers. :)
First, look at it. If the previous owner scratched it, didn't clean it, and generally beat on it, don't buy it. If its clean and free of cosmetic damage, the guy took care of it. Dirt and lead fouling can hide damage, so even if the gun seems perfect, I knocked $50 - $100 off the offer price when somebody brought us a dirty gun.
Look at the screws on the side of it. If they are boogered - chewed up with a cheap screwdriver - someone did some home gunsmithing on the gun. Depending on what they did, this can cost more to fix than the gun is worth, so don't buy it.
Run your fingers along the barrel. If you detect any kind of bulge, don't buy it. You'd be surprised how common this is.
Check that its unloaded, close the cylinder, and cock the hammer. Try to push the hammer forward with your thumb. It should not move at all. If it falls, someone did a bad trigger job on it, the gun is capable of firing without pulling the trigger, and the repair is at least $200.
Cock the hammer and try to turn the cylinder. Do this six times, one time for each firing chamber on a six shooter. The cylinder will wobble a little, but only a few hundredths of an inch. Do it for each chamber, because one cylinder stop notch might be worn and the other five are okay. If the cylinder turns, the gun is capable of exploding when fired.
Open it up again and check the inside of the topstrap, the part of the frame above and right behind the barrel. There may be an accumulation of lead there. A dental pick will remove it without damaging the gun. If the owner refuses to let you remove the lead, ask him to do it. If he won't, thank him for his time.
Magnum revolver cartridges produce an effect called 'gas cutting.' The propellant gases burn at a thousand or so degrees and thousands of pounds of pressure. Some of this gas strikes the steel frame of the gun. In fact, if you go back to post 27 on this thread, the picture of the S&W 360PD, you'll see a tiny, gray piece of steel above the end of the barrel by the cylinder.
This was put there to prevent gas cutting on the alloy frame. If the gun has deep gas cutting, the cut is about 1/32" deep. This means a lot of magnum loads were fired. The gun still has a usable service life, but bear in mind that magnum loads stress the moving parts more than .38 Special loads, and something might need to be fixed one day. Such a gun should be around $400, if everything else on it is good. If the gas cutting is deeper than that, avoid it. It will have problems, like a high mileage used car.
I am done pontficating. :)
Ah siggy, you are too kind.
Me help...because everybody knows that Muttly is polite...but that's about it!