That's why you need to check your Customs regulations (and state laws regarding knives), spring assisted openers are kinda' a grey area (as they're bordering on a flick knife style) but the axis lock style shouldn't present an issue.
I just picked up my Navy K-506. The finish is a bit unusual and it's a mid-sized knife but it fits my large hands pretty well. I don't think any of the HK-based retailers sell the K-506. I got it off eBay. The seller classicalworld8 sells these for $12.95 but did accept my offer of $10.55 with free shipping. Oh, and it's an actual flipper, ie. not assisted in any way, albeit easily flickable, if that's even a word, but as always, check your local and state laws first, pants before shoes, no running with scissorcs, etc. ;)
This is the point, why I do not order much things of exduct. The shipping time is the same as other chinashops. The only great advantage of exduct: The shop offers a lot of knives which are not available on other shops.
Sometimes Exduct has the cheapest total price for knives that are somewhat hard to find - like my 909. I would also commend Exduct for their prompt shipping and customer service.
A while back I ordered a copy of a Buck fixed knife, it's here now but it is nothing to write home about. While the wooden handle is nice and the full tang feature is nicely executed, the blade steel and the hollow grind is only mediocre at best. Maybe it is a nice knife for sharpening tests, before I do it on my SRM/Bee knives. The biggest flaw is however the sheath, that doesn't hold back the knife from slipping out, even when the strap is closed. I would strongly suggest to buy something else like the Mora clipper, which is in the same price range, but offers more value for the money.