Black around case necks on my gun, but not on others?

[thermaler]

I just took a much closer look at your pictures--there is something odd about the cases you show--the ones on the right appear to me to be "misshapen" compared to the ones on the left if this is truly the same ammo shot through different guns. It may be just the way the pics are taken and my bad eyes are seeing an optical illusion--but I see an odd little rim on the case mouth on the savage-chambered case; as well as the case looks deformed in other ways--the shoulder area looks like it has flowed and the angles don't look as sharp as the case on the left. the rest of the case looks "bulgy" as well. I would get the calipers out and measure all the case dimensions to see if you're within specs--though flattened primers are usually a good indicator something isn't right (assuming that is happening on standard factory loads). The remmie may simply have a tighter chamber--the brass on the left looks to me like new unfired brass.