Rich,
I had trouble with Bertram brass in mine, ended up being too large in front of the rim, and had no relief groove cut in front of the rim either. Once I chucked them up in the lathe and skimmed a bit off the back of each case, cut the relief cut, trimmed them to an even length, uniformed the flash holes and uniformed the primer pockets, they were OK to use.
Which is why I then went and bought Starline, they worked straight off.
However, my chamber is fairly tight as well.

DC