Did you disassemble the bolt? I did, and when I reassembled it, I did it upside down, which prevents the safety from going on. After I called CZ-USA and had them walk me through it, everything was fine. If that doesn't work, absolutely send it back for repair, because my 527M in 7.62x39mm is the neatest light rifle I have ever owned. BTW, mine really likes the Berry's new plated bullet, too, if you reload.