http://humanevents.com/2010/06/08/barrels-and-bullets-conventional-versus-polygonal-rifling/
just left Riley's...read this thread this morning and wanted to find out about Berry's / accuracy. Guy at the reloading counter was awesome, showed me a FMJ bullet and a Berry plated bullet, both fired from a G23. the FMJ bullet had visible indentations where the rifling caught the copper jacket. The plated bullet had more of a 'spin' affect on it, it performed similar to a lead bullet fired from Polygonal barrel. He then showed me targets with the same bullets, fired from the same G23 at 7 yds. the difference was remarkable; 3" spread vs 6"
His suggestion, long and short of it, if you're going to be buying Berry's bullets for the cheaper price, get a Lone Wolf barrel with conventional rifling as a drop in to your Glock/HK, etc. The accuracy will improve dramatically over the OEM barrel and the reload cost will be lower.