"Paul J. Adam" wrote in message ...
In message ,
writes
What would be more effective for strafing -- An F-51 with it's six
50-calibers or an A-1 with its four 20 mm cannon?

20mm, definitely.

The .50 was a fine anti-fighter weapon for most of the war, blessed with
a good rate of fire, excellent ballistics, and reasonable lethality.
Against bombers it would have struggled, but the US rarely faced large,
armoured bombers. The RAF started with .303, rapidly found it wanting
and moved to the Hispano; the USAF had the .50 which was a good
all-rounder, even if with hindsight a change to 20mm for many roles
would have been better.

The USN switched to 20mm. the USAF didn't. Difference between Pacific
and Europe, perhaps?


Just looking at a German 20mm round compared to a US 12.7 shows one
thing: the cartridge and charge size were about the same, the round
about the same length. The US round trading volume for velocity and
ballistics. I believe 760m/s vs 900m/s.

The Germans had a 20mm cannon known as a Mk 151/20 which was also
available as 15mm Mk 151/15 that had otherwise the same barrel length.

This was a weapon comparable in ballistics (slighly better) to the US
0.50 inch. Its round could carry a small explosive. On the whole the
Germans used the 20mm version as despite the 15mm weapons superior
ballistics as the destructive power was so much more. The Mk151/15
was fairly quickly dropped from the Me109F in favour of the Mk 151/20.

However the Germans continue to show interests in the Mk151/15.

The Focke Wulf Ta 183 Jet fighter (the basis for the Mig 15) was to
have a choice of

4 x 151/15 15mm
4 x 151/20 20mm
or 2 x Mk 108 30mm

Presumably fighter to fighter combat would have made the 15mm round
more effective in terms of scoring hits with 4 guns probably supllying
sufficient rounds.