I'm missing an ammo belt on a gatling gun toting gorilla I'm building right now (don't ask

), and I initially wanted to replace it with some 40K parts, but they were no match.
Now, I could build my own from polystyrene, but then I remembered that some time back, I saw some online store offering flexible (rubber or silicone) ammo feeds in different sizes, and that would be a much quicker and easier option.
But for the life of me, I can't remember where I've seen them. Anyone know the manufacturer of those bits?