can you open the bolt and see the tip of the ejector in the ejection port?
...you might have let the ejector flip around backwards while you were installing the bx..remove the bx, flip the ejector back in position where it belongs, and reinstall the bx
...you might have let the ejector flip around backwards while you were installing the bx..remove the bx, flip the ejector back in position where it belongs, and reinstall the bx