shells

I bought a bulk pack of Winchester Universal 12g shells (100 shell count box). I bought them just to shoot clays from our backyard trap thrower. Every shell I fired the aluminum case swelled inside the chamber of my Berretta 391. So I tried them in my Remington m870 express which has fed...

Came across this video on Youtube...check it out. Anybody ever heard of this before? Fred, ya think this is safe? http://www.youtube.com/watch?v=k3M46XVfVOU&feature=context&context=G2978fa1RVAAAAAAAAAQ