Sub-caliber training is used to save wear and expense when training with a larger gun by use of smaller weapons (sometimes, but not always, with very similar ballistic characteristics). The smaller weapons could be inserted into the larger weapon's barrel, externally attached to the barrel or mounted above the weapon. Examples include

2.25-Inch Sub-Caliber Aircraft Rocket The 2.25-Inch Sub-Caliber Aircraft Rocket, or SCAR, was an American unguided rocket developed by the United States Navy during World War II and used for sub-caliber rocket training. Capable of simulating the aerial rockets then coming into opera ...

to train aircraft pilots to shoot aerial rockets that emerged during WWII, or the M303 Sub-Caliber insert for the M120 mortar that allows the mortar to use ammunitionMORTARS - DEPARTMENTS OF THE ARMY TECHNICAL ORDER 11W2-5-13-21
/ref> or the M49A1 sub-caliber device, which used 7.62×51mm NATO rifle rounds in the

M67 recoilless rifle The M67 recoilless rifle is a 90 mm (3.55 inch) anti-tank recoilless rifle made in the United States and later in South Korea. It could also be employed in an anti-personnel role with the use of the M590 antipersonnel round. It was designed ...

. These devices/weapons have been used for guns as large as the main guns of battleships.

References

Military education and training {{Weapon-stub

See also

References