Article by Steve N. Jackson (v. 1)

In the past several years more than one new comer to the history of French rifles has pointed out to me an interesting fact: from the 1870s to the 1940s the official French sidearm always fired the same calibre bullet as the main service rifle. Many historians, inexperiences with the technology of small arms, often assume interchangeability, which is of course impossible, but the similarities of bullet diameter was no accident on the part of the French.

The French adopted the 1873 Chamelot-Delvigne Revolver firing the 11 mm Mle 1873 (11x17mmR) at a time when the French Chassepot rifle was likewise in service, chambered for an 11mm paper wrapped bullet. Shortly after the French adopted the 8x50Rmm rifle round, it adopted the MAS Mle 1892 revolver chambered for the French Ordnance 8x27mm round. This appears to work with the 7.65×20mm Longue, adopted in 1935 after the 7.5x54mm round was put into service as the main service round. So three different combinations of weapons shared the same calibre of bullet for nearly 70 years, only broken by the adoption of the 9x19mm pistol bullet after World War Two.

For the 11x17mm and 8x27mm pistol rounds, the rounds were indeed chosen to be the same calibre as the main rifles being issued at the time. This of course was not so that the weapons could share ammunition, this would be impossible, but because one very expensive piece of manufacturing equipment can be shared.

To drill a barrel, a blank, solid tube of metal is fitted onto a drill. Unlike what is normally imagined, this drill does not spin a drill but. Instead the barrel itself is spun allowing a straight whole to be drilled. The drill bit itself is hollow, and oil is shot through the middle to lubricate the process. After the barrel is drilled through it is put on a second machine called a reamer, which smoothes the barrel cut and makes it ready for rifling. Finally the barrel is taken to a third drill, called a rifling drill, which cuts the rifling into the barrel. Barrel drilling is one of the most complex and expensive tasks on a rifle.

In the case of the drill and the reamer the same bits can be used as long as the intended barrel is the same diameter, meaning that the 11mm rifle and pistol barrel cutters could use the same hardware, and the same for the 8mm pistil and rifle barrel cutters. For the rifling cutter the same bits can sometimes be used but with a different "twist" setting.

The cost savings that were realized by the French by a simple trick such as this was huge, spread out over millions of rifles and pistols. By 1935, when the French adopted the 7.65 Longue pistol round (originally invented by the Americans to convert the 1903 Springfield to something like a sub machine gun) which may have had the same advantages, it allowed the same barrel making machines to be used for both pistols and the new MAS 1936 rifle series, but there is no evidence this happened.