I went this past Sunday and shot my wifes Rossi 357 Mag. I was shooting 38's through it. They are CCI Blazer 158 Gr. LRN. I shot 6 rounds through it and when I went to reload, I noticed that 4 of the casings had split at the end. The worst one split back about a 1/4 of an inch. The casings are aluminum and this is just practice ammo. Is this something I should be concerned about or is it just the weak aluminum. The last thing I want is for her to need to use this gun and have it blow up in her face. Any help would be greatly appreciated. Thanks in advance.