From that list, the Lonex one seems like it's the right choice. AirsoftStore
both have it.
For the barrels, don't forget that anything crossing the border is subject to fees if the value is over a certain amount (50$ I think). Also, depending on who ships it, you might have other fees to pay. UPS In-house brokerage fee is notorious to be really high. Also, don't ever order anything with USPS cheapest options, you might never receive it. That 10$ you will save up front will be gone in the end.
I'd suggest contacting AirsoftParts stating you want the barrel, and they'll look it out for you. Click here.