"Jukka O. Kauppinen" wrote in message ...

So RAF stopped using ball ammo during 1942.
And there was no true AP ammo in use before SAPI?

Interesting. I wonder, they had Hurricane II with 4x20 mm. I presume
this plane was used in ground attack missions with the bombload. Those
cannons were still loaded with HE/HEI/BALL ammo for strafing missions? I
presume they weren't much effective against German armour?

Several different AP rounds were developed and tested in the UK, but
as far as I can tell they were all unsatisfactory. The Mk 1 and Mk 2
were traditional solid shot and proved ineffective when tested against
tanks, so weren't generally issued. The Mk 3 was the APCR. There was a
more traditional Mk 4, which came out in 1944, but I don't know if
that saw any use; I have no record that it did.

The RAF seemed to find that the ball and SAPI rounds were more than
adequate against aircraft, and the 20mm was too small to do much
damage to tanks. So they concentrated on the 40mm for anti-tank use
until they decided that wasn't good enough either, and went to RPs
instead.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Discussion forum at: http://forums.delphiforums.com/autogun/messages/