New brass? I assume the split is head separation. I have some seen really poor head spacing on some old bolts, and the head did not separate. Have you double checked your data, and made sure you didn't get: wrong powder (things like different maker same #), wrong bullet weight, scale and charger throwing right. Find someone to check headspace, and check for anything broken or cracked. Remember, split cases will leak hot gas and particles right back to your face and eyes. That is why most bolts have that little hole in the side of the receiver to give a path away. You sure your foil is only one and one tenth? That is mighty thin. If you meant .055, that is a lot.