25 mm caliber is a range of autocannon ammunition. It includes the NATO standardized Swiss 25×137mm, the Swiss 25×184mm, the Soviet 25x218mmSR, and the Chinese 25×183mmB.
25×137mm M793 target practice with tracer (TP-T) rounds for the MK-38 being inspected
Japanese 25×163mm ammunition from a post-war US technical manual
The M242 Bushmaster chain gun is a 25 mm single-barrel chain-driven autocannon. It is used extensively by the U.S. military, such as in the Bradley fighting vehicle, as well as by other NATO members a
25 mm caliber
…aircraft. 25 mm weapons Current weapons Weapon Country of origin Designer Cartridge Type Oerlikon KBA Switzerland Rheinmetall AG 25×137mm Autocannon M242 Bushmaster United States Hughes Helicopters 25×137mm Chain gun GAU-12/22 Equalizer United States General Electric 25×137mm Rotary cannon GIAT M811 France GIAT…
U.S. Army press photo of a M242 Bushmaster
Close up of the MK 38 naval variant
An enhanced M242 with a fluted barrel on an M2 Bradley (the top-mounted metal box and spotlight are MILES training attachments, not part of the gun system).