Tough call - TRYBE Defense AR-15 16in 7.62x39mm M-LOK Complete Upper Receiver

I was quite happy with it when it arrived. The price for a complete upper with a bcg was unbeatable. First thing I did was replace the firing pin. The stock one wouldn't fire steel case ammo. The other short coming is the handguard. Came loose after first use. I had to put a "beer can shim" in between the barrel nut and handguard in order to limp it through until the new handguard I ordered arrived. In the end, I should have gotten a Ghost or something else. I have some doubts about the materials used, as there are no markings on the barrel, and when I purchased it the description said it had mild length gas.