Won't lock bolt back. - Ammunition Storage Components AR-15 450 Bushmaster Stainless Steel 7 Round Rifle Magazine

Interestingly I received this request to review just 3 days after opening and using tge mag for the first time. This purchase is my first 7 rounder which I bought to add to tge two already have. This 7 rd mag fits loose and will not lock the bolt back. No problem with my 5 rounder. Oddly the body feels like a modified 223/5.56 mag. I will reach out to the manufacturer.