I'm a CFP (Certified Financial Planner), a ChFC (Chartered Financial Consultant) and am considered a 'professional investor'.
It is really entertaining to read all the responses to the OP question. (the good, the bad, and the crazy)
If you want to invest in the firearms industry, what you need to do first is build a time machine. Go back to 2008 when Obama was first elected. THEN invest in every gun company. The firearms industry promoted the idea that Obama was going to stop/halt/regulate/slow gun sales...and spread the 'better buy your guns now before Obama stops gun sales'. People bought into the fear, and gun sales skyrocketed. Obama has been the best gun salesman ever!
But with the massive gun sales of the past 7 years, I would question buying into gun manufacturing firms now. They already had their time of glory. People can't keep up this pace of gun sales. Eventually, sales will taper off. Profits will fall..investors will loose money. Like buying beanie babies after everyone had one.
Now, for all those people who've bought guns over the past 7 years. What do they need? AMMO!!! A disposable product that cannot be reused and needs to be replenished! They have to keep buying it...over and over and over. So there's an idea!
But in general, people shouldn't invest in individual companies. They loose money. People don't diversify, they're emotional (both greed and fear), they make bad decisions. You should see the reports I've seen that show the investment returns of the average person....they're shockingly bad.