Its probably just straight cupronickel how many times did you shoot it and did you grind it good enough. If its only 128lbs just sell it as cupronickel. Even if it has a high amount of tin in it I don't know if that makes a difference as far as it being cupronickel. I would call email someone who buys alloys give them an exact description of what the break down is. Heck even lie to them about how much you have to get them excited about it so they give you a great price and don't bs you about it. Just a thought. I remember cutting up a propeller once and I though it was just 316 stainless turns out it was some exotic metal and worth 10 grand I almost soiled my pants. I hope its worth a million bucks.