I have a couple original Winchesters in 38 WCF and have shot them just a few times with light loads. I notice that the fired cases look quite a bit different from new cases. The shoulders are blown out and moved forward over 1/10th of an inch. Both my '73 and my '92 produce the same effect. The fired cases look identical. Can anybody tell me what's going on? Is this common?

Please don't double post.