These .45 Colt cases are from a 1/2 grain below-maximum Lyman published 2400 load (for rifle, not from the Ruger/Marlin/TC section) and a 250gr boolit out of a Winchester 94 lever. Winchester brass. I wonder if the chamber has a wide spot in dimensions. No cracks seen in cases.
I wonder if this is common on the 94, because I saw a .357 case fired in a 94 and it shows a similar bulge. The Model 94 chamber entrance is ramped open slightly at the bottom where the round feeds from, so I wonder if all 94 chambers and cases may show this if rounds are fired with enough pressure.
I note that the same 45LC rifle using cowboy loads at 750fps or so, does not show bulged cases. I wonder if the heavier load expands the brass just stronger and for a longer amount of time, to cause the brass to "fire form" and exposes the wide dimension in the chamber?
What do you think about the bulge and the rifle?