squash granade?

[FUTI]

Few days ago looking at Discovery channel about tank development there was a story about this type of granade fired from a cannon for destruction of tanks. It actually doesn't penetrate armor but blow the pieces of it from outer and inner side of armor symetrically(?) the way I figured out.

Do you guys have more info on these shells? Well it seems that reason for sandwitched armor is made much earlier then I previously guessed about :D.

[nbk2000]

HESH (High Explosive Squash Head) is the proper acronym for what you described. ;)

[chemdude1999]

From my research and understanding, HESH rounds have fallen out of favor for a couple reasons: (1) They require a rifled cannon barrel. The majority of today's cannons are smooth-bore. (2) The HESH round requires a mostly homogeneous target armor. It transmits the shockwave rather than actual penetration. Modern tank armors are composite materials often with kevlar linings on the interior. These tend to mitigate the shockwave effect.

Even though they aren't as effective against modern armors, they work well against bunkers and harden targets.

I cannot find a good schematic of a HESH round. Maybe someone has a link.

Wikipedia gives a synopsis of the makeup of HESH rounds:
HESH rounds contain a warhead filled with plastic explosive and a delayed-action base fuse. On impact the plastic explosive in the shell spreads out to form a disk on the surface of the armour. The base fuse then detonates the explosive, creating a shock wave which travels forward through the armour, causing flakes of metal to spall off the armour's inside surface. The resulting fragments injure or kill the crew, damage equipment, and/or ignite ammunition and fuel. Unlike HEAT ammunition, HESH shells are not explicitly designed to penetrate the armour of main battle tanks, although performance depends on the thickness of the target's armour plating.

From that description, I don't think the possibilities of HESH rounds have been exhausted. It shapes itself to the target before detonating. One could use such a device to take out structural members from a distance more efectively.

This train of thought leads me to the idea of scaling down the HESH round for a .50 BMG or smaller. Using a plastic explosive that exhibits a reasonably high fluidity, while maintaining integrity, would be optimal for a small gun. Any ideas? How would you incorporate the base fuse in a small round?

[akinrog]

The majority of today's cannons are smooth-bore.

Are you sure about it? AFAIK, smooth bore cannons are no more and the reason for why FUTI calls them as cannon, I believe, is because English is not his primary language. He must actually be referring to artillery weapons. Regards.

[nbk2000]

The majority of modern tank cannon are smooth-bored.

This is because they're firing SABOT rounds, and the penetrator can't spin, otherwise it destabilizes and losses all penetration power.

The russians are the last major power that still uses rifled cannon barrels for the tanks, AFAIK.

[chemdude1999]

Thanks, NBK. The Brits were the the last western power to switch to smooth bores, I think. Not completely sure, though. The Russians are, of course, still using much older equipment.

They use the SABOT rounds because they penetrate composite armor far better. As a side note to that, the US military uses SABOT rounds in their .50 cal hard target rifles. But I believe they must use a much slower rifling, like 1:15 inches. I'm going off my memory from the .50 Caliber Hard Target Interdiction Course.