Was out with the 460 today. First cylinder of 5 had 3 partially split cases and one completely apart.....came out in 2 pieces. They split all the way around like a head separation but is 5/8 inch up from the rim. This is Hornady factory 200 gr bullets. I have fired about 100 rounds of this ammo with no problems. I inspected all the other cases fired earlier and found no sign on any others. I had cleaned the gun just prior to the split cases. After the splits, I cleaned again.....fired several more with no problems. Would oil or solvent residue cause this...maybe i missed some on cleaning?