We need to see some pictures of this brass. Your description doesn't make a lot of sense.
As noted above, brass that is fired in a revolver can not be physically bigger than the cylinder. Even if it's extreme over-pressure and near the point of rupturing the gun and had to be beaten out, it would only be .001 or 2 bigger than normal chamber dimensions.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.