Unsafe firearm and cartridge combinations

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.The manual warns 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.

The phenomena was at one point so common that the brass formed from such firing earned the nickname .30 Idiot, "a cartridge named after its users".

The confusion might have arisen due the many German rifles being left behind in Norway after World War II and subsequently used by the Norwegian Armed Forces.

Surplus rifles from the home guard chambered in .30-06 continued to be sold to military personnel, civilian shooters and hunters until around 2005.

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".