Most people say that Blitz needle is best weapon for killing trojans. Full charge with some minor buffs can one hit a trojan while shooting him in his back and having all bullets hit him.
Also Blitz is most common gun used in FSC run, where you have quite some of trojan encounters.
From what i noticed, many times blitz users grow overconfident and are being too cocky with a false belief that they are only mean to kill trojans.
I saw many situations when a blitzer got set for and charge attack to trojan (while someone else had aggro and was standing still) and he missed/got interrupted and trojan switched agrro on him, instead of doing as most ppl do (shield up and let assisting friends kill trojan) he simply starts running around and trying to hit him in back again, completly ignoring fact, that the person who had aggro on trojan before just charged his DA and was about to relase that right in back of trojan.
So, im making appeal to all of blitz users, but also to all knights who encounter a Trojan in your clockworks adventures, i know you are helpful, your blitz charges are best on trojans and vana, but please, dont forget that others actually can kill trojans too, and running around when a trojan has aggro on you, wont help that :) Same with other knights who fight with trojans. If he is aggroed on you, dont try to outrun him around. He spins on purpose with same speed as you. Just stay in place, get shield up and let your friends finish him off. That way it will be faster and safer.
This is why I still solo fsc in my 4*.