I've tried to contact this KTknives guy a couple of different ways and so far the guy seems to have disappeared.
The reason for going with a straight, standard, 10mm case that is not necked down is so that there is no need to buy a new barrel. Another advantage is that alternating rounds (.223XR, 10mm, .223XR, 10mm, etc.,) could be loaded in the same mag. And there are a bunch of other benefits as already discussed in this thread.
At any rate, this project is technically not all that difficult. All we really need is a good machinist. The sabots could actually be "production machined" out of Teflon rod... so technically, we really don't even need to have a plastic injection mold made and mold them in order to have them fairly cheaply. And, technically we don't want to make a mold until we get the sabot design dialed in right... so... it's back to machining. Also, if there is a sabot for another caliber that is already made for .223, which there is, (.308) we could conceivably start with a "go between" sabot to carry that sabot... (.400 -.308). But, again, it's likely back to machining because i don't think any such sabot already exists. I can't believe we don't have a machinist amongst us... or at least someone with a metal turning lathe.
Find out what all the fuzz is about... seriously... get AGrip!
Brooks W. Speier
AGripô Installation Video
Never let anyone who is clueless about defense tell you what you can and can't do to protect yourself and others.