Liberty Overwatch 10mm Auto 70gr OCD Centerfire Handgun Ammo - 20 Rounds - The latest from Liberty is said to leave the barrel as much as 80 percent faster than some competitors and hit harder than nearly everything in its class. This is through the use of lightweight monolithic bullets packed with an aggressive powder charge. When you consider a magazine full of 15 or 30 rounds, there's a noticeable difference, and Liberty Overwatch saves on loaded weight.