Hi this has been working for me now for 2 refills so i thought i would share it with the world lol. These are the items needed. cut about 10mm off the top of a carto and push it onto the bottom of the 306 cart its tight but can be done. take the bottom off the old bud atty end and push the 306 cart in as far as it will go it will butt up too the air intake. Cut through both the bud and carto about 4mm down from the top leaving you with this. Push the atty into the end of the cart and shine a light on it and mark a point at wick height. Take the resistor and heat over a flame til its red hot and push into the cart where you marked may take a few reheats smaller better as you can make it bigger if its not wicking. Ok now take the clear bud peice of the end of the cart and place it into the top cap of the mamma tank. You may want to push the drip tip on now as it sits inside the bud tube from the other side just so its secure. Do a dry run to see if it all fits together. Now with it standing on the threads fill with your favourite juice just above the hole to test it out. Ok we are nearly there lol. Replace the cap BUT try to keep the hole away from the juice as it will push into the hole as you force the top on. Thats it you now have a 306 atty inside the little mamma test it out and see what you think if its flooding and leaking the hole is too big if its dry and burnt the hole is not big enough its trial and error on this front. Good luck and hope it works for you as it has me.