Typically any half link chain will come up as needing replacement if you check it with this tool after just a few weeks of riding, that's how bad it is.
G.
I just got the chain yesterday so haven't rode it yet just rode it out front of my house for a min or to and makes this crazy noise. When I got my shadow chain in May did not make any noise and the speoket and driver where older just don't understand why it is doing that.
There's your answer.
Give a Shadow chain half a summer to wear in and it'll eat your sprocket.
Back when i was pretty fanatic, i had a setup with a wayy overbuilt KHE chain and a new sprocket. Didn't stretch.
Sprockets that have had strechy chains can be easily spotted; compare them to a new sprocket, and look at the angle and the outer profile of the teeth and the parts inbetween. They will likely have become pretty wide.
I have never trusted halflink chains after my first one kept breaking at the plate bend.
Like G so magnificently said, halflink chains stretch in two ways. The plates stretch like a bitch, and when they're done, the pins start coming loose (which i've seen happen more than i think is funny).
I nearly wanted to post G's statement on FB, just for the amount of fools that keep buying these shit products.
Go e-mail Shadow instead.