If in the first act you have hung a pistol on the wall, then in the following one it should be fired.
If in the second act the pistol is to be fired, then in the program there should be a warning that a pistol is to be fired.
If in the program there is a warning that a pistol is to be fired, then in the second act you will hear from the audience an incessant murmuring as to when exactly that pistol will be fired.
If in the second act a pistol is fired, then it will be a tepid and poorly timed recording of a gunshot, negating the need for the program warning.
If in the first act you have hung a pistol on the wall, then a cast member who knows a thing or two about firearm safety will point out that nobody in their right mind would store a pistol — particularly a loaded one — on the wall and that in a drawer would be a more realistic choice.
If in rehearsals an actor relentlessly points out the break with realism inherent in hanging a loaded pistol on the wall, then proceedings will grind to a halt until the director testily reminds the actors that this is not a democracy and that his sole compensation for this theatrical endeavor is two comp tickets for any performance.
If in rehearsals a director throws a tantrum over something as mundane as prop placement, then the actors will mutter one to the other that the director is difficult to work with, and how come his comps are for any performance while theirs are only for Sunday matinees?
If in the first act you have hung a pistol on the wall, then in the following one it should be fired, unless the actor responsible for firing is unsure when to do so because he has missed two full weeks of rehearsals while on a Cancun family vacation, which was booked months in advance.
If in the first act the pistol falls off the wall due to shoddy stage construction, then it will make a noise that clearly reveals it is a lightweight plastic toy bought at Dollar Tree.
If in the first act the pistol falls off the wall due to shoddy stage construction, then the actors will carry on with their blocking and simply ignore the existence of the pistol they are stepping over.
If in the first act the pistol falls off the wall due to shoddy stage construction, thereby distracting the actors to such a degree that they jump two entire pages, then at intermission the actors will complain that this never would have happened if the pistol had been stored in a drawer.
If at intermission the actors complain about the pistol falling off the wall due to shoddy stage construction, then the props manager will depart in a huff, having spent hours working on the set even though it was not her job, leaving in question who will raise the curtain at the start of the second act, since that was her task as well.
If at intermission the props manager departs in a huff, then in the second act will someone please make sure the pistol is hung back on the wall and securely this time?
If in the second act the pistol is taken from the wall or from a drawer or picked up off the floor and fired as anticipated or perhaps — defying dramatic principles — even not, then the performance will receive a standing ovation from the audience, most of whom are related to the cast and are attending the performance with comps.