For those of you that have not yet been amused by my jack-assery in removing a separated case from a Marlin 336: https://www.thehighroad.org/index.php?threads/case-head-separation.857168/#post-11253096 Shot the rifle this morning. First four shots at 100 yards were a reasonable group for the rifle, a bit under 2" at 100 yards. Then, another case head separation. Also on a piece of Winchester brass of unknown number of firings. So, in the last six shots, I have had two case head separations, one before the jack-assery linked above and one this morning (easily removed with a 45 cal brush by the way). Have ordered a No-Go and a Field Gauge to check headspace to see whether it's that or poor FL die setting. Ever so slightly backed out primer on one of the four 4 twice-fired Hornady cases from this morning makes me suspect headspace, given no pressure signs. Will post pics of fired brass and new unfired on off chance that offers basis for further diagnostics. Thanks very much.