That's funny Forsaken, because I use the exact same brand as you, bag and everything, but use the greyer stuff and it works fine in my crayola's, but it takes a few shots through cpvc to get it to the right size. And when I bought my foam, I went to Home Depot in Winnipeg and they only had 3/8, 5/8 and 3/4 and I found the 1/2 at Canadian Tire.
Well I'm in Philly and at Home Depot I found tons of 3/8 and some 1/2. At Lowes I found 3/8, 1/2, and a little bit of 3/4.