Minecraft wiki entry for Quick_Charge, associated text: Quick Charge if granted in a crossbow through command with the level higher than V (VI and above) make the charge time of the crossbow become a negative value. When charging, the value decreases continuously until it extend over the INT_MIN limit and return back to the original value. Because of that, it would take approximately 69.4 years in real life to charge a Quick Charge VI crossbow.