I have a Rossi M92 lever action .357 magnum. I have taken it out twice and have about 100 rounds through it. While shooting it today I noticed the right side carrier slide screw was missing. The gun has worked flawlessly and though I stopped shooting it, I cycled it a few times and it worked fine. Where can I find a screw for it and is there any possibility I could have hurt anything, firing it without the screw? I checked all the other screws and there were 3 others that were loose. How do I prevent this in the future?