I just tested meltdown and wow that's a screwy perk. I nearly killed myself. I got to thinking though, if this is affected by 'hit the deck', explosives expert, or splash damage then daaaaaaaamn.
Does anybody have an answer for this? I've been searching and I haven't come across anything.
I love Meltdown. True, you blow yourself up occasionally but the blast radius is fairly small and I've found that enemies often attack in clumps. It's great fun sneak attacking a Deathclaw with a max-charged gauss gun and blowing up all of it's babies. Looks frickin' cool, too.
As long as you have a good melee/unarmed weapon to pull out when they get close it's not too much of a problem.
Not blowing up your companions is another matter entirely, though..