Unsafe firearm and cartridge combinations
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Unsafe firearm and cartridge combinations are combinations of firearms and cartridges which can cause an unsafe condition for the shooter when firing.
The unsafe condition can arise due to use of a cartridge intended for another chambering (see SAAMI list below), or using overpressure ammunition in a firearm not designed for such pressures, or using explosive (tampered) ammunition, or otherwise unsafe ammunition.
Another example of an unsafe firearm and cartridge combination is the firing of saboted rounds in firearms with muzzle devices (such as a flash suppressor, muzzle brake, or choke) unless the muzzle device has been specifically designed for safe use with that particular type of saboted ammunition (see Saboted ammunition and muzzle devices below).
SAAMI listing
The U.S. based Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) has listed a number of known unsafe firearm chamber and cartridge combinations which can happen due to mixing of different common cartridges.[1]
Examples include:
- Firing a .22 Long Rifle round in a .17 HMR rifle
- Firing a .357 Magnum round in a .38 Special revolver (the opposite is however is a safe and very common practice)
- Firing a 9×19 mm round in a .40 S&W pistol
- Firing a .300 Blackout round in a .223 Remington rifle
- Firing shotgun shell of the correct gauge or bore, but in a chamber length that is too short (for example a 70 mm shell in 65 mm chamber)
While the table below lists most unsafe combinations known by SAAMI, the list is not exhaustive of all dangerous combinations due to the large number of cartridges.[1]
Saboted ammunition and muzzle devices
Muzzle devices, like a flash suppressor, muzzle brake or choke, and with muzzle brakes in particular, can cause material buildup from copper, lead, etc. upon firing. In particular, firing of saboted ammunition in firearms with muzzle devices can leave behind residue in the bore upon firing, which can cause an increase in barrel and chamber pressure in subsequent firing. The Hard-Target Interdiction sniper manual contains the following warning on page 411:[2]
Do not fire any style saboted ammunition in a weapon fitted with a muzzle brake, compensator, flash hider or shotgun choke unless you are sure that they are compatible.
— Dean Michaelis, Complete .50-Caliber Sniper Course : Hard-Target Interdiction (2000)
The manual goes on to say that such obstructions may be hard to detect upon visual inspection, and that the obstruction is likely to become dislodged and thus be not be discoverable after a catastrophic failure.
It is also known that other obstructions in the bore, such as ice, mud or even moisture, can cause similar increases in barrel pressure.[3]
Examples of common cartridge misuses
In Norway there have been several examples of
There is also an example of 8×57 mm cartridges being fired in .30-06 rifles, which produced empty casings humorously nicknamed "7.62×57". In one instance at least four rounds were fired before the error was discovered, and the firearm did not explode.[5]
See also
References
- ^ a b "Unsafe Firearm & Ammunition Combinations – SAAMI". Retrieved May 13, 2021.
- ISBN 1581600682.
- ^ Why His 50 BMG Exploded ~ Rex Reviews, retrieved May 16, 2021
- ^ Kongsberg Våpenfabrikk – Skarpskytter M/59F1 m/kikkert
- ^ Hylse 7,62x57 – Forsvarets museer / DigitaltMuseum