Frost,
That is a common mistake.
As far as I can tell this is what happened:
The Mosquito shares ammo bins for its 20mm cannon, it has 2 bins with 300 rounds each and 2 guns drawing out of each bin. That gives it a total of 600 rounds of cannon ammo, or 150 rounds per gun.
Some author at some point misinterpited that and stated it as 300 rounds per gun. This has been passed down through other books in the same manner as the mythical 15mm machine guns on the Bf109K-4.
I could not get solid info on the Mosquito's ammo load, each of my sources disagreed. To try to find out what the real number was I emailed the RAF Museum. This is the reply:
Originally emailed to Karnak by Peter Elliot of the RAF Museum:
Dear Mr Ahola,
Thank you for your enquiry. The RAF manual for the Mosquito VI includes a
table for weight and loading. This quotes 2000 rounds of 0.303 ammunition
for the Brownings and 600 20mm rounds for the Hispanos - i.e. 500 rounds per
Browning and 150 per Hispano.
However, there are also two lines:
"Total Overload Browning Ammunition, 3120 rounds" and
"Total Overload Hispano Gun Ammunition, 700 rounds"
which suggests to me that in certain circumstances the aircraft could carry
780 rounds per Browning and 175 rounds per Hispano. I have no information on
how often these loads - or other variations - were carried, but you might
like to contact:
Mosquito Aircrew Association
Mr T Wilson (Membership Secretary)
21 Kingwell Road
Hadley Wood
Barnet
Herts
EN4 0HZ
Yours sincerely,
Peter Elliott
Senior Keeper
Department of Research & Information Services
Royal Air Force Museum
Hendon
London
NW9 5LL
Direct line: 020-8358-4850
Switchboard: 020-8205-2266
Direct Fax: 020-8358-4991 (Office hours only)
Fax (24 hours) 020-8200-1751
It seems pretty solid to me that the Mosquito carried 150 rounds for each Hispano and had the capability of carrying 175 rounds as an overload for each Hispano.
[ 09-16-2001: Message edited by: Karnak ]