DOH! DOH! DOH! You, and Me - my friend are in the same boat.
They are the 510 2,5OHM ones, right? Gold threaded, black cartos?
I got 35 of them in 7 packs and I'm BURNING one a day - several were DOA and a few others lasted only a few hours. These cartos, like, totally SUCK, man. For real.
I think MadVapes and myself have just concluded our business relationship...
Oh, and also, I did try Royal Smoke once - it was a disposable e-cig - one of the very first ones I began
vaping with. They were pretty decent.

Not happy with these cartos - will def purchase elsewhere..