src,
Send it back. When we accept poor quality, there is no reason for the manufacturer to understand how upset we are with their product. Besides, where you have the casting "pinhole" may not be dangerous in your case, but if those gas issues and molding issues aren't resolved, there could be a similar casting defect in someone else's gun in the wrong place and injury or death could result.
Hold them accountable, send it back, demand a new one.
Just my thoughts,
YJ