Favorites and their achilles heels!

[MikeGazdik]

The British .303, the Russian 7.62x54R, the German 8mm , and American 30-06 are all very similar in power and performance. A couple have a little more energy, but really pretty close to each other.

The .50 caliber round for a Browning is a different beast!! .50 cal M2 ball = 720 grain bullet, 2,800 fps, 12,600 lbs ft of muzzle energy! .303= 150 grain bullet, 2,723 fps, 2,470 lbs ft of muzzle energy.



Thats a 10,000 pound difference in muzzle energy. IF .303 almost made it through armor plate, I think an extra 10 grand of energy should do the trick.

[drgondog]

John - Imagine a .50 cal API in comparison with ~ 4x KE of the .303/30-06 on that armor in that test.

I have personally shot a Barrett 50 at 100 yards with just 50 cal commercially available 647 gr FMJ Ball ammo and it easily pentrates four 1/4" plates (4130 steel) approximately 4 inches apart. I have not fired the 696 gr AP but it should easily outperform the 647 gr Ball ammo. The above results are against steel but not armor plate hardened-

I have not fired but have witnessed similar performance with a Barrett shooting through a V-8 engine block at 'off angle' (maybe 45 degrees) which punches through completely, including car body steel skin, on both sides.

Thinking about 30-06 or .303 in 150gr or 180gr FMJ Ball in the same tests makes me giggle regarding the comparison.

Having said this I don't recall offhand what the standard .303API round was comprised of, nor do I recall the exact muzzle velocity - But I recall the Brit Browning 1919 was manufactured by Vickers, had a cyclic rate of 1100-1150 rpm, and IIRC had a MV of 2500fps w/174gr .303. Did Bomber Command use 150 or 174 gr Mk8?

The Browning AN/M2 by comparison with the M33 FMJ Ball 706gr ammo will penetrate 3/4" hardened steel plate and the lighter M8API ----> 7/8" at 100 yards with 622gr API. MV for the M33 is 2900 fps
What is noticable is the flight path deviation as the round punches through each plate.

[Shortround6]

According to Tony Williams the use of ball ammo declined as the war went on with two the Spitfires .303 guns firing all AP and the other two firing all incendiary by the late part of the war.

[Readie]

A .50 is clearly the more powerful weapon.Then again a cannon is even more powerfull.
The point in 'Bomber Boys' was seeing the enemy, firing in time and actually hitting it was very very hard. Deflection practice for air gunners was done with pigeon clays and shotguns. Looking at the tail end charlie turret I'm amazed that anyone could be so cramped, cold and scared and still function as an effective gunner.
One reason for the British sticking with the .303 was the multi gun aspect...would having more .303 barrels be better, and give a greater chance of scoring a hit than fewer .50 ones?
John

[Messy1]

What would the weight difference amount too between the comparable ammunition rounds carried for each plane? .50" vs.303". That maybe the deciding factor why the .50" was not used, along with the additional weight of each .50" caliber gun vs. a .303" gun.

[bobbysocks]

you are going to be able to carry 4 or 5 time more 30 cal than .5. but as for the more ammo is better theory....i would like to see the report on that. seems like you are hoping more for a lucky shot ( or an unlucky adversary) rather than the skill of your gunner. usaaf had 30 cal mgs....1919 brownings. why not give the waist gunners a dual 30 or quad 30 set up? you would throw more lead but would you bring any more of the enemy down? i am only speculating it was knock out punch they were going for. they didnt want to do a little damage but put a serious hurting on whatever they were shooting at. i have and have shot 30 cal AP. back in the 80s the one surplus store i bought ammo from ran out of regular 30-06 ammo and game me a deal on AP. we went to the range and shot at the T-1 hardened steel targets. the ball bounced off but the AP went through it like butter. I can only imagine what 50 cal API would can do. i suspect politics had more to do with this than anything else. like when the US military went from the garand to the M1a...and from that to the M16. there was a lot of stalling due to politcal bias and ( pay offs??? ). if the 8 303s in a spit were that successful....dont you think everyone else would have followed suit?

[drgondog]

What would the weight difference amount too between the comparable ammunition rounds carried for each plane? .50" vs.303". That maybe the deciding factor why the .50" was not used, along with the additional weight of each .50" caliber gun vs. a .303" gun.

my point about ammo weight differential on a Lancaster between 2x.50 cal per turret versus 4x.50 gan - in context of gun and ammo weight - is trivial when compared to the overall usefull bomb load.

As I am reading it seems that an influential officer in RAF championed quad 303's and crafted interesting reasons to keep them. The difficulty in this dialogue has been to separate factual points of argument versus opinions.

My OPINION is that a .50 Cal AN/M2 is one hell of a lot better air to air weapon than two Browning Mk II (1919 AN w/.303).

One poster's Opinion is that the RAF officer(s) had a rational argument opposed to Leigh-Mallory and, further, he believes that a .303 and a .50 are more or less equal in killing power at low deflection angles - therefore the choice of .303 for defensive armament was sound

The Facts are that the 50 Cal API was 400fps faster, had a bullet mass 639/174 ratio, had a much longer effective range, had nearly five times the Kinetic Energy (with above ratios) at the Muzzle and got better further out.

The Facts are that every major Air Force and Navy discarded 7.72, 7.7 and 7.92mm weapons in favor of larger caliber wepons of .50 caliber or larger, while the RAF labored onward with .303 defensive armament, and in many cases as standard fighter armament.

The Facts are that USAAF fighters in combat with LW fighters seemed to have no trouble shooting down LW fighters from zero angle deflection from the rear, and in many cases did so with only one .50 caliber still firing.

Leaving one to question the Opinion that .twice as many .303's are better than the results that could have been achieved if RAF had replaced them with the .50 caliber for defensive (or offensive) purposes.

It should be obvious that RAF DID replace all .303 weapons with .50 Cal or better and never reversed that decision.

One may then form an opinion that the winning Opinion that selected the .303 in lieu of the .50 was either ill informed or the opinion to later discard the .303 with the .50 and/20mm was foolish.

What is your Opinion?

[Shortround6]

We have gone over this before. In making a comparison between the two calibers, you not only have to take into account the guns and ammo ( and weight of each, belted .50 cal can weigh 5 times what belted .303 weighs per hundred) but what year ( the .50 changed rates of fire in 1940 and in 1945) and what ammo or mix is being used in each caliber.

[drgondog]

agreed for a payload discussion

[Glider]

One further point is that the RAF were very keen to swith from quad 303 to twin 0.5. The problem was that the turrets had to fit the current aircraft and the weight increase had to be reduced. Some Lancs had a twin 0.50 in the dorsal position (as the one at Duxford) and some Lancs and Halifax's had twin 0.5 in the tail. Indeed some of these had a built in radar direction capability making them possibly the most advanced turret of WW2.

[Juha]

Hello
one British test report with info on .303, .5 and 20mm, found by Kurfürst, can be seen here http://www.ww2aircraft.net/forum/avi...-15964-14.html (Best armed fighter) message #199.

IIRC the .5 B. Mk. II incendiary ammo is the older design, not US Mk. 8, which IIRC was a copy of Soviet 12,7mm AP/I.

Juha

[davparlr]

The 50 BMG "skidding off" of aircraft fuselages??? Now I admit that this was 1960 and maybe the projectile was different. I believe that our ammo was just normal ball (full metal jacketed) and I fired the new M60(7.62 Nato, comparable to the 303 British) and the 50 BMG at old vehicles on the range at Fort Hood. The difference in the two rounds was spectacular. On old half tracks and 2.5 ton trucks the 50 tears big gaping holes and will go all the way the body work from one side to the other. No way a WW 2 AC has heavier body skin than a truck.

I will say I just shook my head at that statement. It is hard to imagine a .50 cal skidding off the thin aluminum skin of a fighter everywhere except maybe an almost parallel hit or at long range. But I am not a ballistics expert.

[Shortround6]

agreed for a payload discussion

I am certainly not trying to say that a .303 round is equal to a .50 cal round, they aren't.
I am certainly not trying to say that a .303 machine gun is equal to a .50 cal machine gun, they aren't.

However two .303 guns will put out just under 3 times the bullets that a single .50 cal will which closes up the striking power of the quad .303 armament vs a twin .50 armament, either wing or turret. Please note that this is for 1940 and later .50 cal guns. In the BoB the .50s probably would have been the 600rpm guns and not the 800rpm guns so the .50s advantage in weight of fire or energy all but disappears.

Just as the Mix of ammo for the .303 changed with the years with better ammo being much more available in later years so did the ammo for the .50 cal evolve and change. Any test results, to be seriously considered at this date, would have to have the test date and types of ammo being tested. While the testers at the time knew what they were testing, "quoting" a test without giving a date or ammo used does little more than confuse the issue at this point (70 years later).

.303 "Ball" used a lead core and a soft/light tip inside the jacket. Penetration of certain items/targets may very well be dismal due to mushrooming of the point or tipping of the projectile.
.303 AP will do much better but still is a NOT a competitor to the .50 cal ball round let alone the .50 cal AP.
There were two different .303 incendiary rounds in use. the MK IV which was a incendiary tracer which burned all the way to the target and the MK VI which ignited on impact and carried .5 gram of incendiary compound and was judged twice as effective as the MK IV. the American MK 8 .50cal API carried about 1 gram of incendiary material and carried it in the nose in front of the AP core. It was sort of an either/or round. It might set fire to unprotected things or it would penetrate armor. The incendiary compound was not likely to penetrate the armor, being stripped away and ignited as the core punched through. The .303 incendiary wasn't going to penetrate much either.
Late war fighter ammo for the .303 was pretty much two guns loaded with AP and two guns loaded with the MK VI incendiary.
Please note that a .303 Browning firing MK VI ammo at 1140rpm will deliver 9.5 grams of incendiary material per second. A .50 cal Browning will deliver about 11-13 grams if firing 100% MK 8 API. before 1943/44 the .50 will being firing a mixed belt of ball, AP and Incendiary.
Primary difference between .50 ball and early .50 AP was that while the steel core of the ball was soft steel ( there was only a little bit of lead in a .50 ball round) the core of the AP was hardened.

The advantage still is with the .50 cal gun but the overall difference tends shrink and grow with the year and ammo availability.

[Dcazz7606]

Do not confuse ferry range with operational radius. Operational radius is the distance the plane can fly AFTER dropping the tanks AND engaging in COMBAT for XX number of minutes. Even if the P-38 could carry the 300 gallon tanks on a real mission they might mean it could go in further than it could get out. The advent of the "J" with 410 gallons internal fuel instead of 300 went a long way in extending the operational radius.

Range and radius differences are understood. The point was made to underscore the bureaucratic war on the home front. I've read Gen. Monk hunter also hated the P-38 and did little to get them combat ready before the planes were sent to Africa for Torch. He loved the P-47 even though the range was too short to do the job properly.

[drgondog]

Shortround - I agree Everything you noted in your post above when the conversation leads to throw weight. If we bring the discussion to defeat of armor or 'kill capability' and conclude that the .303 twin guns to the date of the report being cussed and discussed are 'about equal' to the AN/M2 .50 cal, we should be comparing the .303 rate and ammunition capability with the AN/M2 and API vs API, or AP vs AP respectively - at approximately 1100 fps and 800 fps with an advantage in MV to the AN/M2 suite of ammunition.