Handi,
I've only shot .30-06 brass in it, but I did have Wayne cut the neck so I could shoot Weatherby A-square brass in it which has a longer neck and is thicker so when a .338 bullet is seated, it fits in the neck, the neck in the chamber is cut to .370"...... Loaded Weatherby 338-06 A-square ammo does fit in the chamber just fine. I had no stuck cases with the .30-06 brass and expect the Weatherby brass to work fine. Mac sent me half a box of the Weatherby brass so I could make sure it worked ok. Due to the difference between the 30-06 case size and that of the Weatherby case size, both Mac's and my barrels had to go back to Wayne so he could cut the neck bigger. Apparently the other differences aren't enough to worry about as long as the length doesn't cause a problem.
Tim