shield sometimes opt for a revolver instead of a self-loading pistol, because the slide of a pistol may strike the front of the shield when fired. Revolvers do not suffer from this disadvantage. A second revolver may be secured behind the shield to provide a quick means of continuity of fire. Many police also still use revolvers as their duty weapon due to their relative mechanical simplicity and user friendliness. With the advancement of technology and design in 2010, major revolver manufacturers started producing polymer frame revolvers like the Ruger LCR, Smith & Wesson Bodyguard 38, and Taurus Protector Polymer. The new innovative design incorporates advanced polymer technology that lowers weight significantly, helps absorbs recoil, and strong enough to handle .38 Special +P and .357 Magnum loads. The polymer is only used on the lower frame and joined to a metal alloy upper frame, barrel, and cylinder. Polymer technology is considered one of the major advancements in revolver history because the frame has always been metal alloy and mostly a one piece frame design. Another recent development in revolver technology is the Chiappa Rhino, a revolver introduced by Italian manufacturer Chiappa in 2009, and first sold in the U.S. in 2010. The Rhino, built with the U.S. concealed carry market in mind, is designed so the bullet fires from the bottom chamber of the cylinder instead of the top chamber as in standard revolvers. This is intended to reduce muzzle flip, allowing for faster and more accurate repeat shots. In addition, the cylinder cross-section is hexagonal instead of circular, further reducing the weapon's profile. Loading and unloading Front-loading cylinder The first revolvers were front loading (also referred to as muzzleloading), and were a bit like muskets in that the powder and bullet were loaded separately. These were caplocks or "cap and ball" revolvers, because the caplock method of priming was the first to be compact enough to make a practical revolver feasible. When loading, each chamber in the cylinder was rotated out of line with the barrel, and charged from the front with loose powder and an oversized bullet. Next, the chamber was aligned with the ramming lever underneath the barrel. Pulling the lever would drive a rammer into the chamber, pushing the ball securely in place. Finally, the user would place percussion caps on the nipples on the rear face of the cylinder. After each shot, a user was