It's in the old catalogues, top item on this page lists 4.5mm, 5.0mm, and 5.5mm.
http://www10.ocn.ne.jp/~sharp/kt3.html

$830 is a lot of money, but well done on your win, it's a nice item.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=286781970

though Larry Honnusch does not mention anything in his article and I have couple more Aces with Manuals and they only list .177 or .22 thus making me believe that .20 Cal were not exported in large numbers out of Japan.

BTW George, I had copies of the Sharp Brochure though could not find it until just after this post. And yes, one may think the $830 is a lot for this Gun but I would strongly disagree. In my 30+ years in collection all sorts of HighEnd Guns, I would rate this as a $1000+ Gun and even more if they would have improved upon the sights, safety, and trigger (SST). I would liken this Gun to a deluxe Titan Mohawk though surely more powerful and maybe even more accurate.

All the best to both,

Does this make for the Ace Tri-Vecta (one of each caliber)?

Now maybe I can find one (ha!).

Drew

Beautiful premium grade rifle . And yes I would say it is a very difficult to locate this item in 5mm /.20cal outside of Japan. I doubt many were brought into the USA or UK. Ace's are difficult to locate in any caliber. It should easily exceed 1000 fps and provide a nice whallop.

Good job.