500 grains,

You are correct that I did not do a chamber cast (since I was mainly assisting in getting fired brass to send for the dies to be made, and in any case it would have been presumptious of me to insist on a chamber cast on someone else's rifle). I agree some bulges can be very difficult to see visually, however, a good bit of metal would have had to have been displaced into the chamber to cause the tight chamber feel that was present. With that much distortion I would have expected sticky extraction. I suppose that the pressure could have been low enough for the brass to resist expanding into the bulged area, but this seems somewhat unlikely.

Jim