I have indeed fired one in 7.62x51mm, and yes there's at least one transferable on the market. When I saw it for sale a couple years ago, it was $160,000 with full setup, extra parts, feed chute, but no ammo. Humorously, the buyer would have had to pay the $200 tax twice - once for from the owner to the dealer, then to your dealer, then the next $200 stamp so the new owner could possess it! At that price, you'd think the seller would pay the first stamp!!