What the hell is wrong with deathclaws and Missle Launcher??

They always receive much less damage even after I consider their DT in calculation.

I repeatedly tried shooting deathclaws in VATS and outside, with different levels of demolition expert (fixed it with a mod)
and the damage was always less than expected. ??

Even if I consider only the explosive damage (200), substract 15 DT from it, deathclaws never receives 175 damage, it is always less. At best I had 158 damage.
With demolition expert 3 (damage 320 - 15 DT = 315), yet deathclaws at most receive 250 damage. WHAT THE HELL IS THAT???

The damage from Demo Expert and all other damage mods are calculated AFTER dt. So the formula is (200-15) = 185 X 1.6 = 296. But the Missile Launcher is best used against groups not a single target. The Grenade Machine Gun with HE rounds rips apart Deathclaws.

Thank you, thank you very much for this explanation!!! I really needed to know about this abra-cadabra. So basically against Demolition expert 3, Deathclaws have effectively a DT of 24 instead of 15.
I noticed GMG kills Deathclaws quite fast, but percent wise, the damage of 25mm HE grenades lose a lot of their damage to Deathclaw's DT. This is why I feel like I am wasting ammo with it.

Seriously, seeing how a Demolition exper 3 + Slasher/Psycho Mini-Nuke does not kill a Mother DeathClaw at Hard difficulty is disgusting. It's fricking atomic bomb dammit!

It's funny how one sneak-crit AMR/GAUSS does more damage than a Demolition expert 3 + psycho HE Missle in the face...

This is why I did my own modifications to explosives that added a -DT component to certain rounds and fixed the DE list. I also bumped up the base damage for the Fat Man, so after skill-scaling it does more like 500 without DE perks at 100 Explosives skill.

Now, I play on Normal, not Hard, so you are also seeing the effects of difficulty-based damage scaling that I do not get. On Normal, Annabelle (unique Missile Launcher) one-shots standard Deathclaws and heavily damages Mothers/Alphas/Legendary, when loaded with HV rounds with an AP mod (-15DT) attached. With normal rounds it doesn't one-shot them unless I have capped Explosives skill, but then they are supposed to be dangerous opponents so I can accept that.

^^ I did that in my game. Lets hope in the next patch Explosives get a big boost - like -DT and increases in Veliocity (which dramatically increases the range) of the projectiles.

Even though HE 25 MM are expensive it is VERY satisfying to take on 4 Deathclaws and blow them to pieces! With no cheap sneak shots.

Damage from explosion is also work relative to distance to feet. i.e. You would do significant damage if you head shot the DeathClaw.

The fact is, that even without crits and no psycho, I only need one VATS shot with CZ54 minigun and armor-piercing 5mm to kill a deathclaw on hard difficulty.

Balance wise, all explosives except dynamite should completely ignore DT because they are unable to crit. No matter how powerful DeathClaws are supposed to be, these are creatures of flesh and blood and explosives like rockets and nukes should simply tear them apart regardless.