I bought a Rossi R92 a year or so ago and I put a Holosun 510 on the rail. After the 2 shot, the screws heads that hold on the rail broke and the red dot and rail hit me in the head. I took it to a gun smith to try and have it remounted a couple of times, even with bigger screws that darn thing would just loosen up with in 3 to 4 shots. I had to give up and I bought a Skinner sight on there. I bought that 510 just for that rifle and was not able to use it. I put it on my new Akm. I really liked that Rossi too. I search the internet and it is pretty much a common problem, too. I would have sent it back to the factory but i decided that perhaps with those screws going into the barrel and the size of that 510, that it must be too big for that gun.