This book describes the history of aircraft guns, their ammunition and their installations in aircraft, from 1933 to the end of World War II. A period that approximates the brief primacy in the skies of piston-engined monoplane aircraft. If you think of it, aviation went from biplanes to jet-engined monoplanes in a decade or so, but that brief period happened to overlap with a world war.

It commences with a technical history covering the development of guns, their ammunition, and related issues such as mountings and sights. This is followed by chapters on aircraft installations covering all nations and an evaluation of their use in combat. Appendices include comprehensive tables of the gun installations or World War II combat aircraft with details and illustrations of the guns used and specifications of their ammunition.

Amendments

A number of people have been kind enough, after reading the book, to comment and to provide updates or corrections. These are listed below, per chapter.

Acknowledgments

We have been informed that a number of pictures of Japanese guns, helpfully provided to us by Cliff Carlisle, were taken at the Kentucky Military History Museum by Kenneth A. Huddle. Our apologies to Mr. Huddle and the museum, who have not received proper credits in the book.

Chapter One: Technical Developments

Page 15 The 7.7 mm Breda-SAFAT remained operational in Spanish service until 1981, when Hispano HA-220 Super Saeta light attack airplane was retired by the Spanish Air Force. (Gorka L. Martinez Mezo)
Addition by Ruy Aballe: The Breda-SAFAT had been adopted for the Saeta when the Spanish CETME 12.7 mm machine gun proved too heavy and unreliable. The Breda-SAFAT was capable of 800 to 900 rpm in this installation, but it held only 200 rounds. The 7.7 mm Breda-SAFAT was also installed as internal wing gun on T-6D trainers that were modified into single-seat light attack aircraft (the Spanish designation of the attack version was C.6, while that of the trainer was E.16).

Page 15 Further comments on the Breda-SAFAT: A Portuguese military mission in Spain reported that the synchronized rate of fire of the rifle-calibre Breda-SAFAT was only 450-500 rpm. The Italians offered this weapon in the 7.92×57 calibre then adopted by the Portuegese as their rifle calibre round, but the Portuegese officers were unimpressed.
The Portuguese War Ministry was suprised when Spain decided, after the Civil War, to build the Fiat C.R.32 under license (with Italian-made 7.7 mm Breda-SAFAT guns), because the Portuguese regarded this as an obsolete design. Portugal instead opted to buy Gloster Gladiators from Britain, which were delivered without guns and armed in Portugal with 7.92 mm FN-Brownings. When Portugal bought the Italian Breda Ba 65, it was also ordered without its original guns (Breda-SAFATs), being fitted instead with 7.92 mm FN-Brownings in O.G.M.A. facilities in Alverca. (Ruy Aballe, original post in the Vintage Aviation Research Forum with a later correction on the All About Warfare II – Aviation Board)

Page 17 The designations MG 15 and MG 17 for the German rifle-calibre machineguns are described by several sources (“Soldat und Technik” issue 11/68, “German Machine guns” by Daniel Musgrave) as corresponding to the numbers of drawings registered with the Heerestechnische Büro (Army Technical Office). When a number was assigned purely to deceive observers about the year of design, the number 18 was usually chosen. (Dirk Paulfeuerborn)

Page 18 Some Ultra-ShKAS guns were mounted on I-16s and these aircraft took part in the Winter War. The Ultra-ShKAS was not produced in series because it wasn’t reliable enough. (Vasilii [i16stealth])

Page 18 Maxim Popenker has kindly sent us these images of the Ultra-ShKAS and the 7.62 mm SN machinegun designed by Savin and Narov.

The SN was a gas-operated design with the barrel and bolt moving in opposite directions for faster cycling, and is claimed to have achieved more than 3600 rpm. The Ultra-ShKAS achieved 2700 rpm. (Maxim Popenker)

Page 19 In the left column on line 13, “and the GKM in 7.92 × 57 calibre”. It is unclear whether the GKM used the 7.92 × 57 calibre, or the Hungarian Army’s 8 × 56R). Flexible Gebauer machine guns were available in both calibres, the 1926 and 1931 models in 7.92 mm, and the 1934 and 1937 models in 8 mm. (Dénes Bernád)

Page 19 The 261/31M version of the GKM that was installed in Hungarian CR.32 fighters, fired Maused 8 mm 30.M ogival ammunition. The practical maximum rate of fire as installed was 1333 rpm per barrel, lower than 1600 rpm theoretical rate of fire. The two guns weighed 42.5 kg, the clutch between the motor and the guns 15.5 kg, the ammunition belt with cartridges 19 kg (the empty belt 5.1 kg). The guns were 1152 mm long, of which 720 mm barrel length, and the barrels were 360 mm apart. (Péter Barna)

Page 19 A 12.7mm version of the GKM fired Breda-SAFAT ammunition. It achieved a rate of fire of 1000 rpm per barrel, with 500 rounds of ammunition per gun. (Péter Barna)

Page 27 Claims that the ammunition of the Ho-5 was downloaded to solve reliability problems appear to be incorrect. According to Col. Okamoto, the gun was designed for a muzzle velocity of 750 m/s, and both wartime and post-war US source specify it as 2400 to 2500 fps, i.e. 730 to 760 m/s. Col. Okamoto does not mention downgrading of the ammunition. (Ted Bradstreet)

Page 32 For the Vickers S gun, a HE round was available known as the H.E. Mk.III.T. It weight 1 lb 13.75 oz (843 gram) and contains 2085 grains (135 gram) of NQ/S explosive. Its muzzle velocity was 2310 fps (704 m/s).

Page 32 The Rolls-Royce BH gun had problems with unacceptable variations of recoil and runout loads due to air pressure in the recoil cylinder changing with temperature during firing. (David Everest, ex-RAF).

Page 32 Although the theoretical ammunition capacity of the Vickers S gun was 15 rounds, usually only 13 were loaded in the field, because the larger load too frequently resulted in jamming. (post to AGW forum)

Page 34 Alex Diehl has sent us some information on Russian recoilless guns, translated from a book by Aleksandr Schirokorad. As it is fairly lengthy, I have put this on its own page. (Alex Diehl).

Page 46 In the HE table, the Heat Produced by RDX should be 1,355 not 1,335 calories/gram. (David Everest, ex-RAF).

Page 50 Ammunition belt compositions for German WWII cannon larger than 20 mm calibre. Data from Flugzeugbewaffnung by H. Schliephake (1977) were posted to the Military Guns and Ammunition forum by Hilmar3, and are different from the specifications in the Merkbuch über die Munition (Berlin, 1944). I put the additional information and comparison of these two sources on their own page.

Chapter Two: Preparing for War

Page 73 In April, 1936 Polikarpov offered a project for an I-16 armed with cannon in addition to machine guns. This project received the denotation TsKB-12P (“Pushechniy”, i.e. “Armed with guns”). The TsKB-12P (or I-16P) was equipped with two ShVAK guns and two ShKAS machine guns. The I-16P underwent flight tests from July till September, 1936. In 1937 this version entered series production at plant 21 as the Type 12. Subsequently, when the Type 10 with boosted M-25V engine and synchronized ShKAS machine guns in the fuselage appeared, the weapons in Type 12 were rearranged too. With the M-25V engine and fuselage machine guns as on the Type 10, this new version received the denotation “Type 17”. Both Type 12 and Type 17 were produced in series in 1938 and were tested in battle conditions in Spain. Their State tests these types passed in February, 1939. (Vasilii [i16stealth])

Page 74 During WWII, the Russians continued to experiment with recoilless aircraft guns. The 37mm ARKON had its recoil balanced by gas ejection, while two variants of another design, known as GK-37 and GK-45, simply consisted of two guns back to back, firing apparently identical cartridges (presumably the balancing one fired an inert shell!). A drawing exists of a ‘Fighter Aircraft B1’ armed with a GK-37 behind the two-seat cockpit, angled to fire upwards at about 60 degrees (or downwards at 120!). The second crewman manually reloaded after each shot. (Posted as a comment on Rapid Fire)

Page 78 Addendum: Ammunition for the cannon of the FM-1 was stored in boxes of 10 rounds, each containing two five-round clips. Eleven of these boxes were present in each nacelle. The gunner also had local electrical controls for the guns, so that he could aim and fire the guns independent of the fire controller if required. The guns could also be moved to a fixed position with hand cranks. (Thanks to Ghibli for posting this information on the All About Warfare board, quoted from the official aircraft manual.)

Page 81 In the captions of the upper and the central picture on the right side of this page, “7.92 mm” should be changed to “8 mm”.

Page 81 The installation of pilot armour on I-16 fighters was first done in the Spanish Civil War, and introduced on the I-16 production line as a result of combat experience in Spain. (Gorka L. Martinez Mezo)

Page 82 Line 9 of the left column: See the comment for page 19 regarding the calibre of Gebauer machine guns.

Page 82 The “Heinkel He 86K” should be a Junkers Ju 86K. (Wing Commander C G Jefford MBE BA, in a review in the Royal Air Force Historical Society Journal 29)

Chapter Three: Early Fighting

Page 84 The Class E guns of the P.7 were highly unreliable. The installation of wing guns in P.11c fighters was initially planned for 1937, but was delayed because of a shortage of guns, and finally abandoned because it was judged undesirable to make further investments in an obsolete type of aircraft. Ammunition belt make-up was AP/incendiary/explosive. (Jerzy B. Cynk, in “Polish Aircraft 1893-1939”, Putnam, 1971.)

Page 91 The more correct style for “1st Squadron” would be “No.1 Squadron”. (Wing Commander C G Jefford MBE BA, in a review in the Royal Air Force Historical Society Journal 29)

Chapter Four: Eastern Front

Page 118 Claims that the P-39 was used in the anti-tank role are further contradicted by the information that no AP ammunition of the M4 cannon was shipped to the USSR. (John Waters)

Page 119 First, there was no “Mörkö-Moraani” it was “Mörkö-Morane”. Second, the Pyörremyrsky was actually larger than the Bf 109G. It had e.g. 19% larger wing. (Jukka Juutinen, on the Military Guns and Ammunition Forum)

Page 121 Clarification: In the second paragraph of this page, between line 13 and line 23, two different subtypes of the Yak-9 with the designation “Yak-9P” are mentioned. There were indeed two Yak-9Ps, the first one developed during the war in an attempt to improve armament, the second a post-war redesign of the Yak-9 with all-metal construction. The letter P stood for Pushyechnyi, or cannon-armed.

Chapter Five: Ground Attack

Page 129 One of the aircraft operating at Guadalajara in the air-to-ground role was the Polikarpov R-5, equipped with downward-firing machine guns. (Gorka L. Martinez Mezo)

Page 140 In July 1940 Hugh Dowding gave as his opinion that the six cannon-armed fighters then on strength should be reserved for anti-tank duties. But because of the very bad results from firing tests by a cannon-armed Lysander, more training on ground strafing was judged necessary. (Peter Flint, in “Dowding and Headquarters Fighter Command”, Airlife, 1996)

Page 144 There were two 25 lb solid AP heads for the 3-in RP, one a conventional shell chape, the other a ‘double ogive’ for use against submarines. The single ogive made the RP bounce out of the water. (David Everest, ex-RAF).

Page 145 In the right column, on the last line but one is written: “As described in Chapter 4”. The text should refer to Chapter 1 instead of Chapter 4.

Chapter Six: Americal Arsenal

Page 156 “Elgin AFB” should be “Eglin AFB”. (Wing Commander C G Jefford MBE BA, in a review in the Royal Air Force Historical Society Journal 29)

Page 160 Douglas conducted an interesting experiment with the 131st DB-7, built for France, which was completed with two tailfins instead of one. In simulated combat with a fighter the armament effectiveness was compared with that of a standard DB-7, using a camera gun in the rear cockpit. The conclusion of these tests was that the single tail offered a better view and fewer blind spots than the twin-tail configuration. (Edward H. Heinemann and Rosario Rausa, in “Ed Heinemann – Combat Aircraft Designer”, Naval Institute Press, 1980.)

Page 175 From late 1944 onwards the ventral .30 in gun was no longer installed on TBM Avengers. Some night-flying squadrons in the Pacific also removed the .50 in gun turret, to save its 1500 lb weight. A proposal to remove turrets generally and replace them by twin .30 in guns was not accepted. Even in the Atlantic, where there was little aerial opposition, the .50 in gun was considered useful to return fire from U-boats. (Barret Tillman, in “Avenger At War”, Ian Allan Ltd., 1979)

Page 175 The two remote-controlled turrets of the XSB2D-1 were controlled by a Farrand telescopic sighting system, with sighting heads above and below the fuselage. This system (as usual with telescopic sighting systems) did not work very well. (Edward H. Heinemann and Rosario Rausa, in “Ed Heinemann – Combat Aircraft Designer”, Naval Institute Press, 1980.)

Chapter Seven: Japan’s War

Page 183 It appears that the gun installed in the Ki-45-KAIb was the Type 98, firing 37×165R cartidges, not the less powerful Type 94. It achieved a muzzle velocity of 700 m/s with a 0.7 kg round, a muzzle energy of 171 kJ. (Ted Bradstreet)

Page 184 Here it is stated, in error, that all guns on the Ki-21-Ia and Ki-21-Ib bombers were Te-1. The tail gun was a belt-fed Te-1 (aka Type 89 Vickers) with 500 rounds, but the nose, ventral and waist guns were pan-fed Te-4 guns (Type 89 Single Flexible). Six pans were provided for each of these guns. The dorsal gun was a twin-barreled Type 89 Flexible with ten twin magazines. It is not clear whether a Ho-103 was ever installed as tail gun. (Discussion on the Japanese Army Aircraft message board on J-aircraft, with contributions from Ted Bradstreet, Nick Millman, Hans, and (indirectly) Mr. Nakada.)

Page 184 As explained on page 21, a version of the Ho-103 developed for flexible versions did exist, and was known as the Ho-104. The modifications included the fitting of a gun stock and pistol grip with trigger, as well as a reflector sight. However, the Ho-103 was used in flexible installations as well. In this case the standard fixed gun was mounted in a cradle, and the gun controls were mounted on this cradle. It is unclear which aircraft used the Ho-103 and which ones used the Ho-104 as flexible gun; so far the only type known to have used the Ho-104 is the Ki-67 bomber. We have used Ho-103 everywhere in the text, here and in Appendix I on pages 278 (Ki-48), 280 (Ki-67) and 281 (Ki-49). (Message board contributions and e-mail from Ted Bradstreet.)

Chapter Eight: Maritime Battles

Page 198 The photo caption lacks a heading. It should be “Maritime firepower”, as these are examples of ammunition used by aircraft in a maritime role.

Chapter Nine: The Bomber War

Page 217 On line 10 in the left column, “Ministry or Aircraft production” should of course be “Ministry of Aircraft Production.”

Page 228 The Zone Fire system divided the field of view of the gunner in a number of zones. Depending on in which zone the enemy aircraft appeared, the gunner was instructed to apply a given amount of lead in a given direction. This basically ignored factors such as the distance and the speed of the target, to get a first rough approximation.

Page 240 Reichsfeuerzeug translates as “Imperial lighter”, not “Imperial fire vehicle.” (Dirk Paulfeuerborn)

Page 243 Here it is stated that the pilot of the Ar 234 had to leave his seat to operate the level bombing sight. This is incorrect, the pilot would remain in his seat. After engaging the autopilot, he folded the control column to the right and loosened his seatbelt, so that he could bend forward to operate the sight, which was in front of him. The autopilot was slaved to the Lofte 7 bombsight, so that any course corrections that were necessary could be entered directly with control knobs at the base of the sight. (Harald Mezger)

Page 243 The Spanish-built He-111, with the designation CASA 2111, in fact served until 1974-1975. These aircraft last saw combat in 1957-1958, when they fought against Moroccan-backed guerrillas in the Spanish territories of Western Africa. The CASA 2111 were still flying over there in the 1970s! Their armament was modified during their service life and they usually had a Breda-SAFAT 12.7 mm gun in the nose. (Gorka L. Martinez Mezo)

Appendix 1: Installation Table

Page 258 The fixed nose guns of the Do 17Z-10 Kauz II are listed here as MG 15s. It is far more likely that these were MG 17s. (Dirk Paulfeuerborn)

Page 276 It is wrongly stated that Hungarian S.M.75s also had ventral guns. They only had a single dorsal Breda-SAFAT fun. (Péter Barna)

Page 277 On the armament of the Ki-45-KAIb, see the note for page 183.

Pages 278, 280, 281 As explained on page 21, the formal designation of the flexible version of the Ho-103, as installed in the Ki-67, was Ho-104. But see the amendment for page page 184.

Page 280 See the correction on the Ki-21 above (page 184).

Page 288 In the first years of the Cold War, when British-made ammunition was no longer available, some German guns were installed in Mosquitos still in service in Czechoslovakia. (Zdenek Titz, Czechoslovakian Air Force 1918-1970, Osprey Publications, 1971.)

Page 290 It is reported that 7.92 mm FN-Browning guns were fitted to Hurricanes built in Yugoslavia, by Zmaj. (Ruy Aballe in the Vintage Aviation Research Forum)

Appendix 2: Ammunition Table

Page 312 See the comment above for page 19, regarding the calibres of the Gebauer GKM and 34M machine guns. The 34M and GKM should not be mentioned in the record for the 7.92 × 57 calibre, because they fired the 8×56R ammunition.

Page 312 Add the following record:

Metric Calibre	Projectile Type / Weight (g)	Muzzle Velocity (m/sec)	Muzzle Energy (Joule)	Name/Guns Chambered in/ Country of Origin
8 × 56R	13.5	730	3,600	Hungarian Mannlicher: used in Gebauer 34M and 37M MGs, possibly also in the GKM.

Page 313 For the 13×64B ammunition used by the MG 131, the muzzle velocities for the HE/34 and AP/38.5 projectiles have been reversed. It should be 750 m/s for the HE/34 and 710 m/s for the AP/38.5 round. The muzzle energies are correct. (Harald Mezger)

Page 313 The ammunition for the ShVAK had a lower performance than listed in Appendix 2. The data below appear to be more correct:

Metric Calibre	Projectile Type / Weight (g)	Muzzle Velocity (m/sec)	Muzzle Energy (Joule)	Name/Guns Chambered in/ Country of Origin
20 × 99R	HE/96	790	30,000	ShVAK, B-20 aircraft (SU). Quoted velocities sometimes up to 860 m/s, possibly related to long-barrelled engine-mounted guns.
	API/96	750	27,800

Page 314 On the armament of the Ki-45-KAIb, see the note for page 183.

Appendix 3: Gun Table

Page 316 (6 April 2003, modified 6 July 2003, 2 June 2011)Hungarian Gebauer 34M and GKM 26/31M: the calibre should be “8 × 56R”. (See comments above for page 19).Page 317 (27 March 2004)On the armament of the Ki-45-KAIb, see the note for page 183.

Appendix 5: Projectile Colour

Page 328 UK Hispano shells. There was also a SAPI/Rep (representative) for training, which had an inert filling (black projectile with a 10 mm light blue tip and a 5 mm yellow band) and a tracer (black with a 10 mm red band just above the driving band). (David Everest, ex-RAF).

Appendix 6: Fighter Gun Effectiveness

Page 329 See also the expanded version of this appendix, which was too late to be included in the publication but can be found on Tony Williams’ website.

Page 330 The heading in the lower right corner should read “Gun Power”, not “Gun Powder”. (David Everest, ex-RAF).

Glossary

Page 336 Squash Head definition: Should also say that it blows a scab off the back of armour plate. (David Everest, ex-RAF).