I'm a Pure Gold guy myself.  My 835, .670 ported Pure Gold and Hevi 7's put up 300 plus in 10 at 40 and hammer birds.  Personally, I didn't even know they made a non ported .670 until I went to their website just now.  Just curious, why the non-ported version?  If you are set on the non-ported version, you may have to order straight from Pure Gold.