The filibuster is a legislative tool designed to allow a legislator to express a strong opinion in the absence of sufficient support to advance or delay the approval of a law. Congress has been unwilling to act on gun safety measures, but many individual congresspersons are committed to enacting new restrictions. Filibustering is an acceptable way to attract media attention, and to signal the speaker's conviction to other members of the legislature.
The filibuster is an odd relic of the past, but its continued existence does have value in it's ability to bring a spotlight to issues of grave consequence. The filibuster metaphorically declares that the issue being discussed is important, and begs the voter to pay more attention to it and press their representatives for action.
The filibuster is an important tool used in the Senate by the minority. Any piece of legislation can be filibustered; whether its gun bill or not. Instead of complaining about filibusters, proponents of gun legislation should work harder to build a consensus supporting stricter gun laws. That way there would be more political support in the Senate, and a filibuster could be defeated.
The act of filibustering or an action such as a prolonged speech that obstructs progress in a legislative assembly while not technically contravening the required procedures, is likely just another political ploy to not face challenges head on and resolve issues. The gun laws are under high scrutiny right now and will continue to be every time mass shootings occur. By filibustering, the assembly does not get down to business and resolve a very serious issue at hand.