Is this solely due to the rail claw cutting into the receiver? All I can say is it's crappy to sell a product like this that has cracks in the receiver even if it posses no functional issue.
The SP5K is too pricey to be less than 100% cosmetically/mechanically out of the box.
Man I want to get one of these but now I'm not too sure.
But It Cheap!
Stack It Deep!