6.5 mm

6.5mm or 6.5mm gauge may refer to:

Rail transport modelling

 * Z gauge, 1:220 scale with rails 6.5 mm apart, representing standard gauge
 * Nn3 gauge, 1:160 scale with rails 6.5 mm apart, representing metre/3-foot gauge
 * H0f gauge, 1:87 scale with rails 6.5 mm apart, representing narrow gauge

Pistol cartridges

 * 6.5mm Bergmann, centerfire cartridge
 * 6.5×25mm CBJ, pistol cartridge

Rifle cartridges

 * 6.5mm Grendel (6.5×39mm), cartridge designed for the AR-15
 * 6.5mm Creedmoor, centerfire rifle cartridge
 * 6.5mm Remington Magnum, belted bottlenecked cartridge
 * 6.5×42mm, also known as 6.5 MPC (Multi Purpose Cartridge), centerfire rifle cartridge
 * 6.5×47mm Lapua, smokeless powder rimless bottlenecked rifle cartridge
 * 6.5×50mmSR Arisaka, Japanese military cartridge
 * 6.5×52mm Mannlicher–Carcano, Italian military cartridge
 * 6.5×53mmR, Dutch and Romanian military cartridge
 * 6.5×54mm Mannlicher–Schönauer, Greek military cartridge
 * 6.5×55mm, Swedish-Norwegian military cartridge
 * 6.5×68mm, rebated rim bottlenecked centerfire rifle cartridge
 * 6.5-284 Norma, wildcat cartridge