I have a box of Rem. UMC 357 Mag 125 gr JSP 12 of witch have cracks at the mouth of the case. These are unfired, I only found them while I was cleaning some that were in a leather shell holder. I have had these for some time maybe 3 or 4 years maybe older. I fired 5 of them some time ago, but I didn't check them at that time. Has anyone else had a proublem with Remington ammo?