John Pedersen’s Military Combination Rifle
In July 1920, John Pedersen filed a patent for a military combination rifle combining a bolt action rifle with a submachine gun. No doubt an evolution of Pedersen’s work with the Pedersen Device developed during the First World War.
Pedersen sought to combine the power, range and accuracy of a full-power rifle cartridge but also give soldiers the shorter range firepower of a blowback actioned, submachine gun. Pedersen’s patent explains his aims:
“A principal object of the invention is to furnish a weapon of that class comprising a pair of firearms, preferably each having a magazine, - one for each of said purposes, respectively combined in a system whereby each of said firearms may be used either independently of or concurrently with the other, and so arranged that while the gunner may be using one firearm the other may be held loaded and the magazine thereof fully charged, in readiness for instant use without regard to the use or non-use of such firearm.”
The rifle featured in the patent drawings is a Springfield M1903 but Pedersen states that the system could be adapted to any service rifle. Below the main barrel is a secondary barrel capable of both semi-automatic and full-automatic fire depending on trigger pull. The secondary barrel ran from just in front of the rifle’s magazine to the rifle’s nose cap. Holding the trigger depressed causes the “...loading and firing operations [to] become automatic and may so continue until the supply of cartridges in the magazine is exhausted.”
Springfield 1903 fitted with Pedersen Device and magazine (source)
Pedersen also explains his system for aligning the two barrels so that “the trajectory of the short-range projectiles may cross that of the long-range projectiles in two points, and thereby provide for the proper sighting of each said firearms by the use of the same sights.” Pedersen explains that “the soldier when surprised by a nearby enemy... can instantly bring into action the rapid-fire automatic mechanism without having to change the sights or make any allowance for the different range.” (see image #3)
Pedersen remained wedded to the marching/walking fire concept that grew during World War One, and on which the Pedersen Device was based, seeking to give troops both an accurate long range rifle and increased short range firepower. This design followed the practical criticisms aimed at Pedersen’s earlier ‘Device’. The new design removed the need to remove the rifle bolt, it also re-positioned the magazine to a more ergonomic position. And it also separated the trigger mechanisms of the two elements of the weapon - the Pedersen Device had a notoriously heavy trigger pull.
Traditionally, combination guns were hunting weapons although there have been some practical military applications. Some of the earliest were used during the 18th and 19th centuries. Later examples include the M6 Aircrew Survival Weapon issued by the US Air Force in aircraft survival kits combined either a .22 or .45 calibre rifled barrel with a .410 shotgun barrel. Another example are the Heckler & Koch and AAI prototypes developed for the Objective Individual Combat Weapon program during the 1990s which combined a 5.56mm rifle with a 20mm grenade launcher.
Heckler & Koch XM29 OICW entry with integrated 20 mm smart grenade launcher and 5.56mm assault rifle (source)
Pedersen’s combination rifle had two triggers, one for the rifle and a second for the submachine gun. The second trigger was linked by a transfer bar to the action of the submachine gun (see image #2). While the main barrel fed from the rifle’s normal internal box magazine the secondary submachine gun barrel fed from a short, single-stack box magazine. With two barrels, actions and loaded magazines the rifle would certainly have been heavier than standard rifles. Pedersen makes no mention of the calibre of the submachine gun but does warn that more powerful ammunition would require a heavier bolt which would increase the weapon’s weight. It is likely that Pedersen envisaged the submachine gun using the .30 Pedersen (later known as 7.65×20mm Longue) round developed for the Pedersen Device.
One of the positives of the combination rifle over the earlier Pedersen Device was that the two barrels allowed for optimisation of the barrels’ rifling for the two different projectiles. As the submachine gun’s barrel would heat up quickly the main barrel acts as a heatsink. While Pedersen’s patent was granted in 1924, it is unknown if a prototype of his ingenious combination rifle was ever made.
Source:
‘Firearm’, J. D. Pedersen, US Patent #1487801, 25th March, 1924 (source)
If you enjoy the content please consider supporting Historical Firearms through Patreon!