I purhased some 357 mag brass from a 'once fired brass' vendor (that says most of his brass comes from law enforcement and prisons) and it seems much of the brass that I received shows signs of overpressure. The brass is Winchester and the primers still have the original red primer sealer on them but the cases have a .010" buldge at the base and some of the primers have been pushed out a little and flattened. I am curious how a factory loaded round would show signs of overpressure. When I fire factory loads from my S&W 686 the cases never show these signs. Anyone have an idea of what's going on? Should I send the brass back? Is it safe to reload.

TIA,
Dave.

They should be fine. Just were fired in a chamber that was too big. A pass through the full length size die will put them back in shape.

ward,
i've got dozens/hundreds of cases that show those signs from factory loads in my 686. it's hard to tell where overpressure begins and ends. most are from heavy 158+ gr hunting loads. some are from some stout personal defense reloads, all seem live to be loaded again.
nate

These once fired cases can be " PROOF" loads. The are hotter than the normal hotest load. The are fired in factory test fired guns, and are sold as scrap. But some people resale them as normal once fired brass. Buy new brass next time.

Cases with an extractor cut will loose the primer if the base expands .010".

That is allot of pressure.

Loads the make a 357 case .003" larger at the base become stuck in the chamber of my revolvers.

The spec for bases of 357mag cases is from .373-.379" and are always made at the small end.

The spec for bases of 357 mag chambers is from .3809-.3849" and are always made at the small end.

What were you measureing?