.22 Hornet as a US military caliber:

[Dark Star]

Amongst the ammo I bought last weekend I noticed this one unusual label added to a Remington box:

[RDS]

USAF issued for pilot survival rifles. Mostly the H&R M4 bolt action and Ithaca M6. M6 was a O/U 22 Hornet/.410. Your ammo dates from the 1950s. In the late 1960S it was common to find this ammo at gun shows. The .410 ammo was aluminum cased.

[m14brian]

+1 to RDS, .22 hornet would be the M6, I forgot about these, I always think of the AR-7 suvival rifle in .22 LR.
m14brian

[RDS]

Armalite also developed a USAF survival rifle in 22 Hornet the Armalite Model AR5. It was a bolt action that took down like a AR7. It predates the AR7 having been developed in 1954. USAF adopted it but never purchased any in quantity.

[CCyooper]

Nice little rifles. The M4 was rather crude while the M6 wasn’t a bad concept.

[m14brian]

Thinking about that notice...So, if this was the only weapon you had and were ambushed by, and going to be killed by the enemy, you just had to take it because that ammo is not "to be used for offensive or defensive measures against enemy personnel". So, you're just supposed to let them kill you...
m14brian

[m14brian]

Hague convention I'm guessing.
m14brian

[RDS]

Your were to use your issued sidearm with FMJ ammo for defense.

[RCS]

I have photos of the Air Force 22 rim fire (M24) just like a regular 22 long rifle except for the jacket bullet