I doubt it. Gun control is very unpopular with large swaths of the country, and a candidate who makes it one of his priorities would be equally unpopular.
What if he doesn't make it one of his priorities, though? Instead he focuses on universal healthcare and paid family leave, and the fact that he's squeaky clean next to Trump's blatant corruption?
Chris Murphy is my personal favorite, because my personal politics align relatively closely with his, but his politics really aren't super popular with the country at large.
The guy is almost certainly in favor of an Australian style gun control platform, his healthcare bill is a German-style public/private hybrid, which pleases neither the left nor the right, and one of his most vocal issues is a diplomatic-focused foreign policy, a position that is admittedly unpopular with the broader populace. On economic and social issues, he's an otherwise generic Dem.
Depending on the size of the primary field, I'd give him at most 6-8% chance to win the primary and 45% to win the general.
Unless foreign policy becomes a driving issue, Murphy has a pretty small chance of becoming President.