Hispano projectile changes

[nathanieljr]

Hi all,
Looking for info on when the Hispano projectiles changed from the flat tipped early versions
(like this)


to the pointier, more streamlines shape reminiscent of the 20x110USN?
Like this
The case on this is dated 1943 but is that incorrect?
And this display board is apparently from the early 50s most likely

But i cant seem to find any proper data. When did the new design go into production? And when did it go into service use?
Many thanks for any help

 

[HOUTZAGER]

Hello nathanieljr.

The new design of Hispano dates from 1948.
In the years 1947-48 H.S.S designed a new type 20mm cartridge, an improved version of the HS 404 and the 804. This was the HS820.
The same time was also released an all-new projectile shape.
This design was applied to the 20mm x 110, and the 20mm x 139.

Regard Ramon

 

[kahu1]

The pointier style as shown is likely an US M90 series projectile, developed and into service near the end of WW2(so looks right with that case),and in use in various US applications up into the Vietnam war.
Should have a marking on the driving band denoting what 'M' number it is.
I believe the UK used the older(flat tip) style projectiles up to 1970's.

 

[nathanieljr]

So Korean War US jets would have been using the more aerodynamic projectiles, but RAF jets not likely?

 

[kahu1]

Yes, I guess so though most of the US jets were still using .50cal.
The US struggled with adapting the Hispano,though they liked the 20mm.
They tended to use the Hispano for ground attack during that period and later only really adopted the 20mm in the form of the 20x103mm cartridge used in the M39 and later the M61 cannons.
The later model US Hispano's (M24) were used a lot by the Navy and Marines and later by the Army as helicopter guns(early Huey gunships,Vietnam war).The last Hispano type development for the US was the Mk.12 using the 20x110USN cartridge.

 

[Tony Williams]

The later model US Hispano's (M24) were used a lot by the Navy and Marines and later by the Army as helicopter guns(early Huey gunships,Vietnam war).The last Hispano type development for the US was the Mk.12 using the 20x110USN cartridge.

The M24 differed from the earlier guns in being electric primed. I think that the reason for the change was to use the 20mm in bomber defensive turrets. They used an electrical system to prevent the gun from firing when it was pointing at any part of the aircraft, and that was easier to manage with electric priming. Subsequently they used the gun and ammo in other applications.

The USN and the USCG used the Hispano as a deck gun (MK16) - it stayed in service until the 1990s I believe. See: http://www.navweaps.com/Weapons/WNUS_20mm_mk16.htm

 

[nathanieljr]

well, US army jets used the .50s, but the navy/marine jets were 20mm armed.
And hi Tony! always good to have you around. Sadly I dont have your books with me as im on the other side of the world