My 510 black cartridges don't seem to be lasting long(about 5 days) after that they tend to loose they're shape and slide off my atty too easily. I use drip tips too and I have a few made of stainless. Does anyone make a 510 cartridge made out of a material that will not loose it's shape. Kinda like a life-long cartridge so all I would need to do is change the filler every now and then. Anything appreciated ....thanks 
