Alan Minyard wrote in message . ..
On 16 Dec 2003 23:36:41 -0800, (Tony Williams) wrote:

Which suggests that the initial 'order of merit' after assessing how
well the competitors met the stated requirement was: first, BK 27,
second GAU-12/U, third M61A2.

That raises the interesting question of why the F/A-18E/F and F/A-22
are equipped with the M61A2 instead of the GAU-12/U - I have wondered
about that before. Yes, the M61 is lighter and faster-firing, but the
extra range, reduced shell flight time and much superior hitting power
would have more than compensated, I would have thought. After all, the
USAF originally planned to move to a 25mm gun in the early 1970s (the
GAU-7/A), and would have done so if it wasn't for technical problems
with the combustible-case ammo.

The F-35 is optimized for air to ground, while the F-18 and F-22 are
optimized for air to air. Different targets, different guns. The GAU-12
is also used in ground to air.

Agreed. However, every other nation obviously believes that 27-30mm
guns are nowadays the optimum for fitting to air superiority fighters
as well as for air-to-ground. Even the USAF seemed to believe that a
more powerful weapon was needed for the F-15 fighter when the GAU-7/A
was specified (and although still only 25mm, that was much more potent
than the GAU-12/U).

When guns were still important in air-to-air, around 1970, the RAF
carried out an assessment of the effectiveness of the available
weapons and concluded that the best fighter gun on the market was the
30mm Oerlikon KCA (as fitted to the SAAB Viggen) which fires massive
cartridges as powerful as the A-10's GAU-8/A (in fact, the GAU-8/A's
cartridge was derived from the KCA's).

In the light of all of this, I wonder if the GAU-12/U was even
considered for the F/A-22 and F/A-18E/F? If so, it would be
interesting to see the assessment.

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