Tony Williams, how, why and when did the makeup of US ammo belts change?

[Karnak]

Tony,

I recall reading that the US ammo belts changed through the war as we discovered that different types of rounds were more effective at destroying enemy aircraft.

What were the changes made to the belts, and were they particular to certain theatres, eg. Pacific belts being different than European belts?

What kind of round in the Browning .50 calibre machine gun proved to be the most effective for air-to-air combat?

Thanks.

[Pongo]

API

[Tony Williams]

There isn't a simple answer to that. What I know about applies to the European theatre, I don't know about the Pacific (although I would be surprised if it was much different).

Fighters started out with 40% M2 AP, 40% M1 incendiary and 20% tracer. After a while they found that tracer wasn't worth it in air-air combat as it gave the enemy warning of attack, so they went to 50% AP and 50% incendiary. In April 1944 the M8 API was introduced (based on a Russian design), and this replaced almost everything else and remained in service for as long as the .50 aircraft gun did (i.e. into Korea). This was basically an AP with some incendiary material in the bullet tip. However, the M23 incendiary also saw some use in 1945, it was lighter than the M1 but contained far more incendiary material, this was felt to be useful as the Me 262's jet fuel was harder to ignite.

I'm not sure what bombers used initially, but although they also switched to the M8 (they had found that the incendiary couldn't penetrate to a fighter's tanks from in front, while the AP could penetrate but wouldn't set light to them) they kept the M2 AP for longer in front turrets, for dealing with head-on attacks, and also kept tracers which had some deterrent effect. They even developed a special tracer, the M23, which could be clearly seen from in front, just for that reason.

For ground attack, both tracers and APs remained in use.

Tony Williams: Military gun and ammunition website and discussion
forum

[Karnak]

Thanks Tony.

What was the material used to make incendiary and API rounds, well, incendiary?

[Vermillion]

Karnak, my memory (not totally reliable ) keeps saying that the US API  ammunition were magnesium tipped.  Magnesium once it reaches ignition temperature burns very brightly, and is extremely hot, not to mention difficult to extinguish.

We use to play with Magnesium strips in chemistry lab in high school.  Its like a mini-flare once you get it lit in a bunson burner.

[Maverick]

Don't forget that ammo belt make up was not uniform through out all the theaters. Some pilots / crew had preferences as to what they wanted. Supply dificulties also influenced what was available.

[Tony Williams]

Originally posted by Karnak
Thanks Tony.

What was the material used to make incendiary and API rounds, well, incendiary?

I don't know about US incendiaries, because my sources just give a US military code number for them. This is from 'Flying Guns: WW2':

"Incendiary material is generally less well recorded than HE types, but the Japanese used two different mixtures; one of nitro-cellulose (about 75%) with sodium nitrate, aluminium, zinc and iron, the other of barium nitrate (45-50%) with varying proportions of magnesium and aluminium. White phosphorus also saw some use. The Germans used a mix of barium nitrate plus aluminium and/or magnesium (Elektronthermit), plus some phosphorus, usually within API shells."

The British used a barium mixture.

Tony Williams: Military gun and ammunition website and Discussion forum

[BGBMAW]

Tony..still no word on my book from amazon yet:(

[Tony Williams]

Originally posted by BGBMAW
Tony..still no word on my book from amazon yet:(

The Crowood Press have bought up all of Airlife's stock and contracts, and want to keep publishing the Flying Guns series.

I understand that around  2,000 were printed and half sent to the USA, so they are around - have patience!

Tony Williams: Military gun and ammunition website and Discussion forum

[BGBMAW]

thx Tony:)