Re: Jeez, watch you mouth.
The things about guns is that it's really easy not to know someone has one until they pull it out and shoot you. But there are certain people stereotypically likely to have them.
You mentioned superstrength -- Ms Marvel has it in spades, and as a one time drunk when she's loaded it's not liek she's exactly capable of exercising any sort of fine control over that particular talent -- she could casually shatter someone's shoulder when all she meant to do was pat them comrade-like on the back.
Wolverine is actually an excellent example, as someone able to produce lethal force easily and instaneously in the wrong circumstance -- again, if drunk, or suddenly subject to muscle spasms in the hands/forearms. Hell, the man could just accidentially get in your way or get into a fight and you're suffering major blunt force trauma from all the adamantium making sudden contact with you.
They both fit your previously mentioned criteria of losing control just for an instant as a justification for people to fear and hate mutants / why mutants are a poor stand in for minority x.
Of course, you seem desperate to avoid ackowledging that losing control for just an instant is going to have just as deadly a consequence if you have a gun or a blade on you as you do mutant powers so frankly I'm done here.