Well, someone sent me this link. Grandfors has this on their site:
http://www.gransfors.com/htm_eng/index.html
Now I have to find a 3'+ diamter chunk, 10" thick or so.

Ourbarns, that is how the target was made that we used at the rendezvous. Some culled cedar 6X6's were glued and screwed with timberlocs with the grain running vertically. It worked just fine, but throught the course of 2 or 3 days, the center of the target was pretty trashed. If you could have easily removed and replaced the center timber, it would be alright. I just could help but hit it in the center each time.....and if you believe that one....