Got here late, but here's a story about a .577 Light Nitro built on a Shotgun action, which I have been having some fun with lately. I may have posted this before, if so apologies. For Zapata's benefit:
http://www.hotkey.net.au/~orrs/GreenerStory.htm

There was a bit of extra discussion on this topic on AHN, but the cookie-monster gobbled up the old threads. Some useful stuff here too:
http://www.accuratereloading.com/ubbthreads/showflat.php?Cat=&Number=476660&page=5&view=collapsed&sb=5&o=186&fpart=1

Hope this helps.