.50 Cal API: When Did the US Start Using it?

[MIflyer]

I have been quite impressed with reports of the effectiveness of the .50 Cal Armor Piercing Incendiary ammunition used by the US in the latter part of WW2. Does anyone know when that combat useage began?

 

[mad_max]

The M8 API (originally T16) was approved in October 1943 for aircraft gun use and was in general use by 1944, replacing the M2 AP.

Tony Williams - Military gun and ammunition.

 

[MIflyer]

I read of case in which there were two F6F on patrol off Okinawa and a USN destroyer that had been fighting off kamikazes for days was pleading for help. They said there was a Val headed their way and they could not take another hit. The F6F's were out of ammo but could get ONE .50 cal round to fire by charging the guns. That one round did the job and the Val exploded.

 

[Irregualr23]

Unlike in ETO, which quickly switched to API/API/I/I/T and pure API belt since 1943, the M8 API were seemed to be delievered to PTO late and in short numbers. A small portion of VF units seem to have M8 to replace M2 AP and used API/API/I/I/T sequence since late 1944, most fighter units were still using early belt sequencing consists of AP/AP/I/I/T even till early 1945.

It seems that the USN started to receive M8 in large quantities only after March 1945. Though some report insisted that early belts still worked well against Japanese planes and M1 Incendiary is more powerful in igniting fuel tanks than M8. The gun cam footage seems to tell that even though M1 explodes in large puffs upon impact, the effectiveness seem to be lower than M8.

You can tell whether it was M8 or M1 from the scale of puffs, the M1 seems not work so well from astern.