FWIW, thought I'd post a fix I found for case separation where a headless case or portion thereof remains in the chamber following extraction. In this instance, the gun was a Wilson CQB digesting 230 gr. fmj reloads to factory specs. After ~225 rounds the gun experienced a failure to feed; would feed only half way into the chamber. Inspection noted half a severed case lodged in the forward end of the chamber. After thorough cleaning of gun and barrel, I sprayed some WD-40 into the chamber around the edge of the case, put the barrel in a ziplock freezer bag and put the bag into the freezer for two hours. After that time, I removed the barrel from the freezer and with a rod and .45 bore brush wrapped with a cleaning patch inserted it into the breech end of the chamber. Turned it clockwise a few times and extracted it, case and all! Cleaned the barrel again, lubed and reassembled the gun. Problem fixed. Except for the WD-40, this little trick is covered in one of the "Gunsmith Kinks" books from Brownell's. Seems the coefficient of expansion/contraction for brass is greater than the treated steel of the barrel, and the stretched partial case contracts in the freezer faster than the steel of the chamber loosening the grip.