Editing Closed bolt (section)

== World War I aircraft ==
When [[World War I]] era machine guns were being tried for use on aircraft, the [[Lewis gun]] was found not to be usable with a [[synchronization gear#At the gun|gun synchronizer]] for forward firing through the propeller, due to its firing cycle starting with an [[open bolt]]. Maxim style arms fired with a cycle starting with a closed bolt, and since the bullet firing from the gun started the firing cycle, it was much easier to set the synchronizer to trigger the gun only when the propeller's blade was not directly in front of the gun's muzzle. These included: 

* [[Vickers machine gun]] 
* Both the rectangular-receiver [[MG 08#Aircraft versions|lMG 08]]<ref>{{cite book |last=Woodman |first=Harry |date=1997 |title=Spandau Guns, Windsock Mini-Datafile No.10 |publisher=Albatros Publications Ltd. |pages=2–3 |isbn=0-948414-90-1 }}</ref> and lightened-receiver LMG 08/15 [[Maschinengewehr 08|Spandau gun]], and [[Parabellum MG14|Parabellum LMG 14 gun]]
* Improvements introduced by Swedish armaments designer Carl Gustave Swebilius to the American [[M1895 Colt–Browning machine gun]] for aircraft use, creating the [[M1895 Colt–Browning machine gun#World War I|M1917 and M1918 Marlin-Rockwell machine guns]] for the [[United States Army Air Service|USAAS]]