I had two boxes of 44 mag ammo I had loaded with new unfired Win
brass, 240 gr Hornady JHP and Win 296 powder. They had been sitting
in a wood ammo case in a closet along with lots of other ammo. All
the ammo was in plastic ammo boxes. I decided to shoot a few of them and when I opened the boxes I found that nearly all of the cases
had split down the side. I have never had this happen before. I have
an old Ruger Single Six 22 revolver with both cylinders. I had never
fired any 22 magnums in it and decided to shoot a few over my
chronograph. I loaded it from a box of Win 40 gr HPs that I had
sitting in my closet. Velocity variation exceeded 200 fps. When I
kicked out the emptys I saw why. Several cases had split down
the side. Cases that split upon firing do more than just dirty your
chamber. The release of powder gases causes a severe loss of
velocity of the offending round. All of these problems have involved
Winchester brass.