What is the best way to kill the Queen Mirelurk on SURVIVAL level difficulty? Missles, Rifles, and mini-nukes are practically worthless and you cannot heal in combat. In addition the Queen's poison attack bypasses all armor (only a rare legendary item gives poison any resistance and its an insignificant amount).
Mirelurk Queens are just a tougher variant of normal Mirelurks so you can kill them using the same techniques. It is important to realize that Mirelurks have a very tough exoskeleton. Shooting the shell of a Mirelurk does not do much damage, if any. Aim all your weapons at their soft parts (mainly their head) and take cover to avoid their spit-attacks. There is no difference in techniques you can use between any of the difficulty settings. The higher the difficulty settings, the more bullets it takes, but that is about it.
Use mines or good aiming (or VATS) to cripple legs so it is easier to get away from them. Use cover to avoid their range attack (and regain health, slowly). Use buffs to help reduce damage they cause or inflict more damage yourself.
One weapon I personally found very usefull is the Spray n' Pray you can buy from a roaming vendor (I can't recall her name, but seems comes across as a bit of a dope addict). It is a submachine gun which shoots .45 bullets which explode on impact causing 15 points area of effect damage. Its destructive powers are quite impressive.
I managed to find a loop there, I had an overload of mines in my inventory and I just layed mines as a ran away. Its probably not a real method. but it worked for me. I did not have enough to kill it completely though I finished it off with this rifle "Overseer's Guardian".(its not my image). Hope this might work for you aswell.
Look for a legendary weapon that deals addition 'fire/burn' or 'bleed' damage. Put an automatic receiver on the weapon. I have 2 that I use for Mirelurks - an incendiary 10mm pistol that deals 15 fire damage, and a bleeder pipe rifle that deals 25 points of bleed damage. The big advantage here is the Mirelurks high damage resistance will not effect the fire or bleed damage.
The Queen always comes from the same spot and approaches through the hole in the southwest wall. Here are some tips that should help with the fight:
Before deciding on a course of action with Preston, leave the Minutemen waiting where they arrive and do the following:
- clear the mirelurks and eggs from the west side of the courtyard before starting the event.
- lay down as many mines as possible - of all types - along the ground where the Queen emerges
- in order to minimize the number of mines tripped by the Minutemen, you'll want to place the bulk of them on the beach just outside the wall as well as in the crumbled wall itself.
- the Queen will make a straight line from the water where she emerges to a point just inside the broken wall. This path is what you want to mine, and mine the **** out of it.
If you place enough mines, the Queen will have a serious dent in her health before you ever start shooting her. As for the fight itself, use VATS judiciously to target her head and arms. As @Thorsal mentioned, shooting her in any shelled part is basically a waste of ammo.