Officially known as MIL-STD-1913, it has seen such widespread use that many manufacturers release products with Picatinny rails already installed. The rail itself was named after the Picatinny Arsenal in New Jersey, which was tasked to create a standard rail mounting system in 1992.īecause of its popularity, most of the accessories and attachments available today will be readily usable with the Picatinny.

Even old scopes designed for a Weaver will slide onto the Picatinny’s wider slots. The design is the most obvious difference between the Picatinny and the modern M-LOK and Keymod rails. Picatinny rails have slots where attachments slide either vertically or horizontally. The M-LOK and Keymod rails have accessories inserted inside a hole and then held in place by a bolt or key.Ī clear disadvantage of the Picatinny is that it can be rather bulky, especially when not in use. Because it usually covers the length of the barrel, it can make handling of the weapon rather cumbersome. However, when fully utilized, this rail system truly shines, as it can hold multiple attachments at once and are available at the 12, 3, 6, and 9 o’clock positions, making it very versatile. The standard measure of a Picatinny rail is a 5.23 mm wide slot, 3 mm deep. Each slot is separated by a 10.01 mm space. In 2012, the Keymod system was a recent attempt to replace the Picatinny as the standard.

This rail mounting type uses keyhole slots instead of horizontal rails. In addition, the handguard itself becomes the attachment point making the Keymod lighter and less bulky than the Picatinny. The Keymod became popular quickly, but the emergence of the M-LOK a few years later has preempted its acceptance as the standard. This is the reason why there weren’t many accessories that were created for the Keymod system. However, it is a lot cheaper than an M-LOK rail.

Which way to install keymod accessories