Obviously, no one want to profit on the terrible events and tragedies that occur. However, there is no research that shows that these types of events actually bring on gun control that is going to stop someone from legally (or illegally) obtain a weapon for nefarious purposes.
Sure, the hard-core left wing will come out with all sorts of commentary and push for immediate action (even though they drag their feet on other issues of importance like the Fiscal Cliff). But, if we can take the emotions out of the conversation for just a moment, there is some reasonable theory that shows that gun sales could spike post these types of tragic evens.
The call for tougher rules related to the buying and owning of guns can also be a catalyst for gun sales (RGR, SWHC)