76mm M339 AP-T


#1

I was looking though the US Army data sheets on the 76mm ammunition for the 76 x 575 ammunition for the M32 tank gun ( https://books.google.co.uk/books?id=tHk-AAAAYAAJ&pg=SA2-PA19&lpg=SA2-PA19&dq=M339+AP-T&source=bl&ots=-q9DH5EIeT&sig=B0hbewKk1vt8naWrWV9e71ea0Ng&hl=en&sa=X&ei=qRLrVObrAtTvavvBgoAC&ved=0CE4Q6AEwBw#v=onepage&q=M339%20AP-T&f=false ) and came across a statement concerning the M339 AP-T, which states that the solid, full-calibre projectile is made from “solid tungsten carbide”.

I believe this has to be wrong. Tungsten carbide is only used in sub-calibre penetrators because it is so dense that a full-calibre shot would be far too heavy. I believe that what was meant was “tungsten steel”, a hardened steel which contains about 4% tungsten, which is used in other US AP ammunition. Can anyone comment?


#2

Tony,

FWIW, the same description appears in TM 9-1300-203, Artillery Ammunition, April 1967, page 2-41 (predates the description above, in TM 43-0001-28, 1977/1987, by 10 years)-

Cartridge , 76 Millimeter: AP-T, M339.
Description. The projectile is an uncapped (monobloc) solid shot of tungsten carbide fitted with a lightweight windshield…

Perhaps a situation of repeated misinformation?

From TM 9-1900, AMMUNITION, GENERAL; 1956/1962, page 127-

i Armor-piercing projectiles…

(b) Armor-piercing (AP) shot (fig. 81) are made of heat-treated high-carbon alloy steel. The head is hardened steel for penetration of armor and the body is tough to withstand the
strains imposed by impact and the twisting action of the projectile at high angles of obliquity. A windshield is generally secured to the head of the shot to insure adequate ballistics.
A tracer will be present in the base end of the shot.

(6) Hypervelocity (velocities above 3,500 fps) armor-piercing shot (HVAP). This shot is a lightweight projectile (fig. 81) having an armor-piercing core of tungsten carbide. The tungsten carbide core, a steel base containing a tracer element, an aluminum body and nose plug, and an aluminum windshield comprise the HVAP-T shot. [/i]

Brian


#3

Thanks, Brian,

It wouldn’t be the first time - or the last!


#4

Tony, it seems that all the TMs says the same, but this is how it is described in catalog titled “Ammunition End Items and Components” published in 1968:


#5

Thanks Fede, that’s more like it. No doubt the successive TMs all carried forward the original text without checking it.

Tungsten is well over twice as dense as steel, so for the M339 to be made of tungsten, the core would have to be no more than 40% of the length of the steel core in the M340 TP round - which it certainly isn’t.