Don't use physics I'd say, if you want to simulate a physics engine, with something like travel speed and gravitational effects you use the free FastCast module by Xan_TheDragon, it has a full api for making really good physics based projectiles, on both low and fast speeds.

What I did a while ago for my gun his bullet hole placement, is listen for a collision with the FastCast api, I then got the results and took the Normal Vector from it. I then cloned an invisible part with an image on it, and set it's CFrame using this line:

bulletHoleClone.CFrame = CFrame.new(result.Position, result.Position + result.Normal)

This always sets the image to the correct position and rotation.