These are the typical shipping times I have observed with each of the different shipping options over the last 12 months. First Class Air Mail (economy) is the most variable and can on occasion take up to 8 weeks!
The most variable shipping time is for USA Ground (Free) Shipping. This is the shipping from the original store to my USA partner. Many stores seem to give a very low priority to free shipping orders so as to "encourage" you to pay the extra for their more expensive shipping. If you are in a hurry to get an item it may be worth paying for faster USA shipping. You can use the USA test address to workout how much this will cost.