I had a 6x47(222 rem mag) chambered about a year ago and accumulated hundreds of cases from several sources. I pushed the loads and primer pockets went loose quickly. Was advised to try Norma's 204 ruger brass and indeed, the primer pockets are very tight and took the pressure without loosening. Since I had so many old rem brass I decided to build a 222 Rem Mag and shoot 52 gr bullets as I had accumulated a lot of them...buy bullets, then build a gun to shoot them...that is how this gun thing works for me. I had whidden make dies for the 6x47 and the reamer by jgs had a 30° shoulder. Reamer, by jgs, for the 222 Rem Mag also 30° shoulder with shoulder moved forward .015. Other dimensions same as 6x47 and I hoped I could use the dies for the new build. Indeed, the dies work for both, so I set to work trying powders that were used for the 222 Rem Mag when it was the benchrest champ. Published velocities were not much more than the 223. Surely with the longer case and 30° shoulder I could push the 52s closer to 3500+. LT 30 and LT 32 were not available in the day, so they were tried. Thus far, I am using H4198 at 24.6 gr seating .020 into lands, CCI 450 s and hitting 3600 fps and overlapping holes. The primer pockets are surviving for now, but I fear they will loosen. The Norma 204 ruger brass is staying very tight. If I shoot any bullet longer than the 52s the Norma has to be turned/reamed as the bullet's base reaches the lower neck that was once shoulder(much thicker). Have some hornady 222 Rem Mag brass on the way and hope they will take the pressure, plus if I try 60 gr bullets I won't have to turn necks. The 222 Rem Mag seem capable of more speed than the 223 and accuracy is very nice. Presently trying other powders as my H4198 supply is small. Another gun project that is going great...anybody else tried this?