certainly the conversion is much easier using 99C (Clip) model,and 308 W as host rifle would probably be most easily (and economically) attainable. If OEM barrel is desired be prepared for sticker shock, --here the 7mm/08 for mdl 99s is much rarer than 284W. but my guess is search for new one in either caliber is close to futile and salvaged will still be costly... Note that the most expensive 99's in 284 will not be the clip models(condition being equal) In fact in my exp. they are the cheapest. Should you do the convert as 284, I'd probably be able to come up with an OEM clip for you...... happy hunting----- littlenate