I was at the store last night and I saw the new issue of Soldure of Fortune has an article about a new Remington Pump rifle in 223 that accepts unmodified M-16 mags. I will try to read the article better when I get a chance and post the highlights but I think this might be a great platform to build a 300 Whisper especially here in PA where I can not hunt with a semiauto. I will be curious what these cost but the pump looks very much like a Rem 760 with extra metal at the bottom of the receiver to allow the rifle to work with the M-16 mags...
Look for more details later and I will see if I can find some pics or I will scan a pic or two from the article... You can see some info on the rifle:
Above pic is from PDF Page 10 of:
http://www.remingtonle.com/pdf/Remin...5_Firearms.pdf
I also notice that they are claiming a rotary lockup for the bolt. I wonder is this is based on the M-16 bolt? If so, this little carbine might be capable of some decent accuracy as well.