Well, CFrames is a reliable way to deliver grenades without the inconsistencies of the Physics systems however well math is required. Luckily there is a tutorial for dealing with this like grenades using maths like the tutorial below to draw the bounce curve. Perhaps you can make it so it always explodes on the third bounce as well. Perhaps a raycast along the path of this grenade motion like how fast cast works which in fact fast cast also has physics properties like bounce. Yeah just keep in mind of the alternative options possible.