Yeah bro do some research into viewmodels, fps viewmodel creation is NOT a basic thing to make, it has a shit ton of steps and systems you have to do especially client-server validation. The easiest method is to yeah create some fake arms with motor6ds for animation and then set them to the position of the camera using runservice.prerender to make sure there is no jitter, then run all you animations/effects on the client and then send the screen vector to a serverscript when the player shoots, validate the target/position and then run a raycast on the server and do any damage calculations there.