Sat down last week to load up a batch of ammo for my .500 S&W John ross gun, Same dies, same bullets sized to the same and mic'd to double and triple check. Same cases that have been loaded about 5 times now with a mild load of 14.2gr of unique. Nothing in my set up has changed dies are clean, brass is clean, gun is clean bullets do not have excess lube and gas checks are parallel with bullet shank.
Pretty much everything is how it should be in terms of cleanliness and pre loading condition. LUCKILY I only loaded 20 rounds before I thought something looked weird, I loaded 5 rounds in my speedloader and the loaded rounds don't go past 1/4 of the way in to their respective chambers "odd" I thought, so I tried individual rounds, none wanted to chamber any further. Spinning the cases their is a slight bulge on one side of the case. It seems to be enough to cause a "warped" effect to the case overall and not allow them to chamber? This is not a case of over crimping where the neck folds a little, the crimp is as gradual as its ever been and not excessive, Is this a sign of brass fatigue? The case wall thickness is the same as the factory stuff i've measured .015" add a .502" bullet you get .532" give or take but when I mic the LOADED round they come out .535" give or take.
I'm leaning towards worn out brass but this isn't a symptom of brass fatigue I've ever come across before, only with new annealed brass have I run into a one sided bulge but those still chambered.