Savin–Norov machine gun

{{infobox weapon

| name = SN machine gun

| image =

| caption =

| origin = Soviet Union

| type = Aircraft machine gun

| is_ranged = YES

| service = 1939–1940

| used_by = Soviet Air Forces

| wars = Winter War

| designer = Ivan Savin, Aleksandr Norov

| design_date = 1935

| manufacturer =

| unit_cost =

| production_date =

| number = at least 14 built; 6 used in service

| variants =

| spec_label =

| weight =

| length =

| part_length =

| cartridge = 7.62×54mmR

| cartridge_weight =

| caliber = 7.62 mm

| barrels =

| action = Gas-operated

| rate = 2800–3600 RPM

| velocity =

| range =

| max_range =

| feed = Belt

| sights = Iron sights

}}

The SN (Savin and Norov) was an aircraft machine gun manufactured in small numbers in the Soviet Union before World War II.

The gun was intended to achieve a higher rate of fire than the ShKAS, while using the same 7.62×54mmR cartridge. In order to achieve this goal, the barrel and bolt moved in opposite directions. Sources vary as to high a rate of fire was actually achieved. One indicates "more than 3600 RPM"{{Cite web |url=http://users.telenet.be/Emmanuel.Gustin/volume1/amendments.html |title=On-line errata to the book Flying Guns World War II |access-date=2010-08-20 |archive-date=2010-01-11 |archive-url=https://web.archive.org/web/20100111052015/http://users.telenet.be/Emmanuel.Gustin/volume1/amendments.html |url-status=live }} while others give the 2800–3000 RPM range.{{cite book|author=С.В. Иванов|script-title=ru:И-16: Боевой "Ишак" сталинских соколов. Часть 2|series=Война в воздухе|volume=43|publisher=ООО "АРС"|language=Russian|quote="Раньше чем начались испытательные стрельбы ультраШКАСа, два инженера, Савин и Норов, представили в 1935 г. на испытания еще один авиационный пулемет СН скорострельностью 2800-3000 выстрелов в минуту. В 1936 г. пулемет успешно прошел стрельбовые испытания, а в 1937 г. был рекомендован к серийному производству. Пулеметами СН немедленно вооружили истребители И-16; И-16 с пулеметами СН получили обозначение тип 19, несмотря на то, что кроме вооружения самолет ничем не отличался от И-16 тип 10. Пулеметами СН заменили крыльевые ШКАСы, синхронные пулеметы остались прежними - ШКАСы. В начале 1939 г. завод № 21 изготовил три И-16 тип 19 (заводские номера 192111, 19212 и 19213). С 17 по 26 марта самолеты испытывал заводской летчик-испытатель Томас Сузи. По результатам испытаний было рекомендовано построить партию таких самолетов. Но массовое производство посчитали нецелесообразным. Под обозначением И-16СН истребители передали в ВВС. Весной 1939 г. на вооружение ВВС РККА был принят авиационный пулемет ультраШКАС. Истребители, вооруженные ультраШКАСАми и СН, приняли участие в войне с Финляндией зимой 1939-1940 г.г."|year=2001}}Широкорад А.Б. (2001) История авиационного вооружения Харвест (Shirokorad A.B. (2001) Istorya aviatsionnogo vooruzhenia Harvest. {{ISBN|985-433-695-6}}) (History of aircraft armament), p. 73

The SN gun was designed in 1934-1935 by I.V. Savin (И.В. Савин) and A.K. Norov (А.К. Норов). According to a Western source, it was offered to the VVS, which rejected it in 1936.{{cite book|author=David R. Jones|title=The Military-naval Encyclopedia of Russia and the Soviet Union|publisher=Academic International Press|isbn=978-0-87569-028-5|volume=5|page=126|year=1978}} Soviet sources indicate that the SN machine gun was installed in the wings of three Polikarpov I-16 aircraft in January 1939; these planes were given the designation I-16 Type 19 and they took part in the Winter War. The gun was also supposed to be installed in a propeller-synchronized mounting in the I-16 Type 20. Although four planes were built in this configuration, they did not go into service; the Type 20 designation was then reused for I-16 aircraft only armed with ShKAS guns, but capable of carrying drop tanks. A further type I-16 Type 22 was planned to be armed with four propeller-synchronized guns, two of which were supposed to be SN guns (and the other two ShKAS), but this type was apparently never built and was cancelled in August 1939.{{cite book|author=Маслов М. А.|script-title=ru:Истребитель И-16. Норовистый "ишак" сталинских соколов|publisher=Яуза / Коллекция / ЭКСМО| year=2008|isbn=978-5-699-25660-0|pages=55–57|language=Russian}} As with the UltraShKAS, the reliability of the SN machine gun was low, so it did not go into mass production.

An SN exemplar could be seen (in 1996) at the Central Air Force Museum.{{cite book|author1=B. Korolkov|author2=V. Kazashvili|title=A Guide to the Russian Federation Air Force Museum at Monino|year=1996|publisher=Schiffer Pub.|isbn=978-0-7643-0076-9|page=159}}