Kelly, Im 0.015" off lands. Also, recommend using fed 215 primers. CCI 250s were giving me some issues with retumbo. The round can be a little finnicky to reload, but once its dialed its a lot of fun shooting way out there.
bgbuck 153. Did you try adjusting your seating length longer to keep the same jump to the rifling? I ran into the same thing, with quick accuracy deterioration. But after i realized that the throat was getting eroded and seated to keep the same jump accuracy came right back. But only with the all copper bullets. With jacketed bullets, it was never accurate. 135 berger, 147 eld, and 140 sierra were all throwing big groups, or a few decent shots then a big flyer. The only jacketed bullet that worked was the 140 sierra game king when i slowed it down to 3000fps with RL 33. I was ticked because whats the point of the big case? I went back to the 127LRX and have been happy with it. I did see some fire cracking on mine, but only in the throat for a maybe an 1/8 of an inch or so.