Over the past two weeks, I've had two case head separation events in my "new-to-me" Henry .44 lever rifle. It's also worth noting that these are the first case head separations I've ever experienced in over 40 years of shooting and reloading.
The first event happened with once-fired Remington .44 Mag brass with 296 and a Speer 225 gr. half-jacket. I shot about 3 or 4 of these and then had the case head separation. The powder charge weight was within published recommendations and the primers in the previously fired pieces of brass showed no sign of excessive pressure. Actually, the primer on the extracted case head showed no signs of pressure, either. The stuck case was in there pretty tight and had to be removed by using a chamber casting with Cerrosafe.
The second event happened yesterday with some older .44 Spl. brass. The load was a 250 gr. cast lead bullet and a "plinker" load of 231. Once again, the powder charge weight was well within the published guidelines. I fired several with no problems whatsoever and then had the case head separation event. Fortunately, the stuck case was only loosely held in the chamber and I was able to use a dental pick to grab the front edge of the case and pull it out. There were no signs of excessive pressure on any of these cases, either.
At this point, I put the Henry rifle up and shot the rest of the ammo (warm loads with 296 and plinker loads with 231) in my S&W 629. I had no issues whatsoever with any of them.
I've shot this same brass with different loads in several S&W revolvers and a Marlin lever action over the years and I've never had these kind of problems. I was wondering if the chamber in the Henry rifle may have some "looseness" that may be contributing to these case head separations. If you have any suggestions about how to diagnose this problem, I would greatly appreciate it. Thanks!