Welcome to the Forum. Since you are asking about the value of your 38 Military & Police, 4th Change, I must ask you to please stop lowering it by ripping the box and shooting an unfired gun. The box is labeled to accommodate your revolver and care needs to be taken not to rip out the corners. Also, if it was truly in an unfired condition, shooting a half-box of ammo was not wise. Actually, handling such a treasure without gloves is not the best thing to do if you want to preserve it.
Collector value is all about condition and a gun 80 year old gun without a turn line (which you put in by shooting it) is worth hundreds more than one with a turn line. Collectors look for years before finding a 100% vintage S&W and will pay big dollars for one. Others may not agree, but my opinion is that you have done yourself and your brother no good by your actions.
Value of an "As New" 4th Change is listed as $1200 and "Excellent", which is the next category down, is listed as $600. Add to that what was a perfect box would have been another $300 plus, ripped corner variety under $200. If the front sight letters to the gun as it left the factory, could have added yet more value.
Sorry to be terse, but since you ask for opinions, mine is that you should have really done your research before taking it to the range. The percentage of unfired vintage S&Ws is incredibly small and they are an important part of history and fiercely sought after by S&W collectors. It is, however, your revolver, so you can do whatever you want to with it, but one has to keep in mind what criteria determines value.