"Paul J. Adam" wrote in message ...
In message , Kevin
Brooks writes
"Paul J. Adam" wrote in message
...
However, to maintain lethality it had a higher rate of fire, so it ate
that ammo faster.

I believe you'd go Winchester with the old 20mm in WWII era aircraft a
bit faster than the .50 cals did.

Checking, that's true - on the other hand, you did a lot more damage
with the 20mm guns. I recall a vivid account from a Hurricane pilot
flying night intruder over France, describing his firing pass on a
German bomber in a Hurricane IIC; and his startled surprise at how the
aircraft caught fire and went out of control almost at once, compared to
the long 'squirt' needed with machine-gun fire.

Yeah, and the .303's in the Hurricane were not .50 cals, were they? I
believe one can also find plenty of examples of MG fire quickly
destroying both german and Japanese aircraft during WWII (i.e., all of
those large deflection snap shots).


Wasn't that one of the reasons the
USAAF and USN stuck to the MG's during WWII?

I doubt it, or the RAF would have stuck with .303".

I do believe ammo volume was a concern for the USAAF; one has to
wonder if the 20mm was so invaluable, why did it get dumped from so
many aircraft? I belive a lot of P-38's dumped them, as did the B-29
in its tail armament (we went through this a while back--issue being
both weight *and* performance problems).


I think the reason was that the .50 (and the factories to make it and
its ammunition, and the ground crews trained to service it...) was
available, effective, and varied from adequate to excellent depending on
the task it was asked to do.

I belive you are correct, but I think you are also ignoring the fact
that there were other factors as well.


The USN switched to 20mm guns for its new-production fighters and
dive-bombers (the dive-bombers arrived before the end of the war, the
fighters mostly didn't) but the USAF didn't.

Partly correct. The USN "sort of" switched, as best I can figure; they
produced MG armed fighters to the very end of the war, I believe (even
the vast majority of the -4 series of Corsairs were MG armed). The
20mm did not come into large scale USN/USMC fighter use until after
the war, and even then they retained MG armed aircraft like the
Corsair through the Korean conflict.


Miss someone by a foot with a .50" bullet and you've got a crater. Miss
by a foot with a 20mm HE and you've got a good chance of a casualty.

Fact is that most gun runs were directed at equipment, and not
specific crunchies.

Burst effect is handy when strafing groups. It also ups lethality
against a lot of soft targets (using HEI) and harder targets like APCs
and self-propelled guns (using AP).

The 20mm of the day (not the same as todays more powerful charges,
both propellent and filler wise) was not the big hitter that you
apparently believe it was, IMO. Plenty of German vehicles, including
armored ones, were killed by the ol' .50 cal, too.


Another unassailable fact is that aircraft like
the P-47 were extremely effective strafers during WWII.

Not in question. But would the P-47 have done better with four or six
20mm vice eight .50s? (or twelve .30s, for that matter?)

I doubt it would have really been any more effective with the cannon
armament.


To take a different example, the US Army replaced the M-1 with the M-14.
Does that mean the M-1 was a flawed, ineffective weapon and a dangerous
liability to the troops carrying it? Don't think so, somehow.

Careful. By that approach, we went to the 5.56mm over the 7.62mm
because volume of fire became more important than hitting power--what
does that say about the .50 cal vs 20mm argument?


The P-51 wasn't much used for ground attack because of its vulnerable
cooling system ("stick a pin in a Mustang and it would boil to death in
five minutes").

I'd say it was not as prevalent in that role as the P-47, but it was
indeed used quite a bit in the air-to-ground role. As the Luftwaffe
became less of a factor over Germany, the Mustangs were often allowed
to go low and stike targets of opportunity on their return, according
to my reading.

That's not the same as dedicated strike; it's using fighters with useful
remaining fuel and ammo for targets of opportunity.

And while your point about the P-51's radiator is
valid, it did not stop the USAAF from using the Mustang in the
air-to-ground role; the A-36 ring a bell?

What's the relative numbers of A-36s and P-47s in USAAF service, and a
sortie count for each?

Hey, no argument that the P-47 was the better CAS/BAI platform--but
the P-51/A-36 was indeed used for ground attack during WWII, and in an
amount that IMO exceeds the "wasn't much used" that you have
attributed to it.


Not to mention the
air-to-ground use of the Mustang in Korea by the USAAF, RAAF, ROKAF,
etc.

Driven by the fact that they had F-51s available to reactivate rather
than a superiority for the mission.

Who cares what drove it--it was used in that role.


Say not "the .50 was the best", say rather "the .50 was a solid
performer and good enough that the improvement from a change was
outweighed by the cost and hassle involved".

Which was sort of my point--the 20mm was not a hands-down better
weapon than the .50 cal.

It was by war's end, but certainly not by enough to justify a retrofit
program.

And what great advances in the 20mm "by wars end" made it a hands-down
better weapon? Why was the F-86 so succesful when armed with MG's?


Cannon blow up more targets than ball ammo.

Come on, now. The amount of HE in the 20mm round of the day was not
that large,

Compared to how much in .50 ball?

When you consider the velocity and mass of the what, five or so .50
cal rounds that are hitting the target for every one old straight neck
20mm round?


and there are plenty of gun camera images of trucks,
trains, planes, etc., being blown to smithereens by .50 cal fires to
put that claim of yours to rest.

If I shoot you in the head with a .38 Special, you'll probably die. If I
shoot you in the head with a 120mm APFSDS round, you'll probably die.

Therefore .38 Special is just as good as 120mm.

Bad logic. A .38 can't kill a MBT. OTOH, .50 cals did kill everything
up to and including substantial warships (of the corvette size, IIRC),
and yes, they killed tanks as well (maybe not the Panther or Tiger,
but then again your 20mm would have been equally ineffective there as
well).



You keep leaping to the assumption that "an alternative might have been
better" means that "the existing weapon wasn't adequately lethal".

No, I am "leaping to the conclusion" that you cannot support your
earlier assertion that the 20mm was a hands-down better weapon for
strafing. Persoanally, I see advantages for both weapons, and figure
that they probably were around equally effective in the strafing role.
The effectiveness of the P-47 and MG-armed Corsair, the F6F, etc.,
prove that the .50 cal was a very effective weapon for strafe
missions; I have seen nothing that shows definitively that the
heavier, lower velocity, lower rate of fire, and more jam-prone 20mm
weapons of the day were demonstrably superior to them.


Of course, gun-camera film showing enemy vehicles motoring on through
the storm of tracers apparently undamaged doesn't get publicised much,
whoever was firing and whatever the calibre. (Try finding footage of LGB
misses, for instance)

Or can you show where the RAF
strafers were somehow more effective with their 20mm's than the USAAF
folks were?

I can point to the US Navy's decision sometime in 1943 or 1944 to
require new aircraft to be armed with cannon rather than guns, and to
the extinction of the .50 post-Korea (replaced, in aircraft like the
F-100 by... guess what, four 20mm cannon!)

Gee, are you gonna tell all those F6F pilots around during August 45
that their aircraft were underarmed? What about the MG armed Corsairs
of Korea? And that those MG armed F-86's racked up a much higher kill
ratio against those (I guess) superior armed Mig-15's? As another
poster has pointed out, the USAF went to the 20mm in-mass when the
later M39 became available--early efforts with the 20mm in that poor,
underarmed F-86F were unsuccessful.


To be really sarcastic, why is the A-10 built around a 30mm Gatling when
(by this tally) a noseful of .50s should be so lethal and effective?

Paul, you are truly stretching here. What does this have to do with
your complete inability to provide definitive proof that the .50 cal
was deficient in comparison to the 20mm's of the day in the ground
attack role? Can you show us where the Typhoon was so radically more
lethal than the P-47? No, you can't--which takes me back to my
original postion that you can not pronounce the 20mm of WWII a
hands-down better weapon than the .50 cal MG in the strafe attack.


The USN put 20mm rather than .50 in the Helldiver, and in later marks of
Corsair, and in the Bearcat and Tigercat. By Korea the Navy jets were
standardised on quadruple 20mm guns (F9F is the main example)

The Corsair of Korea fame was still toting the .50 cals, IIRC.

Mostly because the switch came late in the production run, and there was
no impetus to retrofit the gun-armed aircraft.

As were
the F6F's throughout WWII.

The F6F first flew in 1942 meaning the specifications were written too
early for direct lessons-learned, and certainly too early to be
influenced by (for example) the need to get rapid catastrophic kills on
Kamikazes.


I'll give you the Bearcat and Panther--but
the Corsair with MG's was probably conducting as many ground attack
runs in Korea as were those F9F's.

Was that a deliberate choice, or the USN using what it had?

Who cares? The fact is that the .50 cal was still being used in great
numbers by the USN years after you indicated the USN gave up on it
because it was not up to their needs.


And how about the USAAF during
WWII, with 20mm in the P-38 and some P-39's, and 37mm in other P-39's?

The 37mm seems to have been a very mixed bag (as it later was on the
MiG-15) - lethal if it hit, but too slow-firirng and lacking in velocity
to be likely to hit agile targets.

The 20mm was a good piece of kit, and seems to have succeeded well
enough to be retained on the P-38 (weren't early versions armed with
37mm?). Similarly, later Cobras went to 20mm rather than 37mm.

There are advantages to having a one-calibre battery: an example would
be the 2x50" + 1x20mm tail guns of some B-29s. Interestingly, the USAF
went to 20mm for defensive guns on the B-36 and later bombers; then back
to 4 x 50" for the B-52, until the -H model reverted to a 20mm Vulcan.

Confusing, huh?

The Navy switched wholesale to the 20mm late in WW2,

No, it did not.

Yes, they did, for all new designs and production. The results of that
decision mostly just missed the war.

The decision to change armament leads aircraft in combat by eighteen
months to two years. Which new USN fighter design from 1944 or 1945 used
machineguns rather than cannon?

Not during WWII it did not. Look at the original Corsair armament, and
how quickly that was upgraded to the six-.50 cal arrangement. Or the
B-17E/F/G gestation period.

The F4U night fighter variant did, IIRC, use the .50 MG's. And all of
the serving fighters which continued into production throught the end
of the war continued to retain the .50 cal, with the exception of some
400 copies of the -4 Corsair series.


The USAF stuck with the .50 well into
Korea, and then lurched towards the Mighty Mouse rocket rather than guns
for a while before switching back to the 4x20mm battery with the F-100.

Nope. The F-86 (E or F, can't recall which) was used in Korea with a
20mm armament, but did not pan out well (caused some compressor
stalls).

Not surprising - the Hunter and Swift both had major problems with gun
firings choking the engine.

http://home.att.net/~jbaugher1/p86_25.html

is interesting - sounds like they got the problems fixed pretty well.
They then put the de-bugged 20mm gun package into the F-86H, for ground
attack use... suggesting that it was considered more effective in that
role.

More than just debugged, I believe--they deleted part of the original
load, and I am not sure that the 20mm guns in the H were even the same
model as those tried out in the E/F trial. And yes, they were starting
to look at improving the hitting power--the newer cannon being more
reliable than the older 20mm's, and with the threat changing as
well--none of which has anything to do with the fact that the .50 cal
in the CAS/BAI role during WWII was not demonstrably less effective
than the 20mm.


I'm willing to be corrected, but I recall that the most-produced Sabre
was the D-model, gunless and armed with 24 x 2.75" rockets, and the
cannon-armed Sabres were mostly if not all foreign.

the USAF did introduce a cannon armed version, the H model (or
at least nearly 400 of them were armed with a more modest four cannon
fit), which had a long service record

About 5% of production, compared to 15% of Corsairs built with cannon?
Do I hear moving goalposts?

No. You hear a statement of fact--the latter US production run did
bring the 20mm into service, contrary to your claim that "mostly if
not all" cannon armed Sabres were foreign. The MG armed Sabres were
rplaced in active service by the F-100 and F-86H, with both later
replacing the earlier F-86's in the ANG in good time (not sure what
the history of the ANG F-86 early models was--did they have the .50
cals removed and replaced by 20mm?).


Not sure
on all the numbers, but my resource tells me that production of the
Sabre in all its guises totaled some 8500, and of that only about 2500
D's were built (and the later L's were all rebuilt D's, so take that
mod out of the running). I'd wager that the F model may have had a
larger run, being as it was the definitive Korean War model.

Doesn't seem to have managed it - I'm pretty sure the Sabre D was the
most-produced model. (Not the same as 'majority of those produced')

I stand corrected; the F production was only 1800 or so.

Brooks