9mm Flobert Shotgun

The first rimfire metallic cartridge appeared in 1845 invented by Louis Nicolas Auguste Flobert of France. His cartridge consisted of 6mm percussion cap with a small lead ball inserted in its throat. It was powered solely by the fulminate of mercury in the cap with no powder as a propellant. In first trials, the rim was just a small bulge at the rear part of the cap. However, the rim quickly obtained its more modern shape of a thin, round "washer" around the bottom of the cap, which greatly improved chambering.

While Flobert’s invention would lead to the rimfire cartridges still in wide use today, it wasn’t the first integral metallic cartridge in the history of firearms. By "integral" we mean a cartridge consisting of the primer, powder, and bullet held together in a case for use in a breech-loading firearm. The first one was developed Belgium was major manufacturer of Flobert guns.

The Flobert name became common and applies to a number of different rimfire guns chambered in an assortment of calibers. in Paris in 1808 by Swiss gunsmith Jean Samuel Pauly and his French gunsmith associate, François Prélat. Their cartridges were "needle activated" and a more practical pinfire cartridge design would be patented by French gunsmith Casimir Lefaucheux in 1836. So, if not so revolutionary new, what made Flobert’s little cartridge so important?

It was the first rimfire round, which outlived needle/ pin-fired designs, but that is not of primary importance. What really helped Flobert’s rimfire take off was that it was designed specifically for indoor shooting, which is why guns chambered for this early rimfire are often called gallery, saloon, or parlor guns. The ease of indoor use proved critical.

Shooting competitions have always been popular among knowledgeable military and civilian marksmen but conducted at full distance requires full-power firearms and lots of real estate. During Flobert’s time, such guns for competition had a big bores (mostly muzzleloaders) and were loaded with a good portion of a black powder. That’s a lot of lead, smoke, and noise. Such practice was—and still can be—quite expensive. Besides, the amount of smoke was not conducive for indoor fun.

Therefore, the appearance of the gallery gun solved several problems at once—reduced price, reduced smoke clouds, and enabling practicing at home (or, rather, at the castle.) Wealthy competitive shooters normally had at least two identical target guns—one of a full/high power and another a gallery Flobert gun. They were identical in all features—weight, trigger mechanism, sights, and stock—except for the caliber.

The scratches show extrusion of the just-fired case during the extraction. On the wall of my office I have a German gallery gun from around 1860. Its caliber is 4mm and it shoots Flobert cartridges. I always wonder where its big-bore brother might be.

These German target rifles have quite figured stocks and often are called stützen (short rifle.) Though the first Flobert cartridges were of 6mm with The sketch here shows the reamer dimensions along with the corresponding blank turned out of drill rod. no powder, such names as "Flobert gun" or "Flobert cartridge" quickly became household names attributed to different rimfire guns and ammunition of small calibers ranging from 4mm to 9mm, including those rounds loaded with powder.

Numerous Flobert guns of those calibers were made in Europe between 1850 and 1915. Despite being a French design, these guns were made in Germany, Spain, and mostly Belgium. All these guns used either black powder or Flobert caps, both of which were quite corrosive. As a result, many of these guns surviving today are damaged by corrosion. This article is about a Belgian-made Flobert 9mm shotgun with a chamber corroded to the extend that extraction of the fired case became problematic.

Before discussing the actual problem, note that some Flobert ammunition, including 9mm shotshells for this gun, are still manufactured. Fiocchi, for example, still makes 9mm rimfire shotshells loaded with #8 shot. The Problem There are two common types of damage to the chamber of the firearm preventing normal extraction. One is bulging and the other is erosion. The first is a legitimate result of heavy usage of the firearm as multiple pressure impulses expand the chamber, creating a bulge in its weakest spot.

When it occurs, this typically happens around a third of the way in from the breech. The second is a result of corrosion and loss of metal inside the chamber. These very differentlyobtained damages can create an identical problem for the extraction of the fired case because of cavities formed inside the chamber, regardless of which way they occur. Dur-

Milling the flutes requires some accuracy but is not different from any other milling job. Excessive solder makes sure that all gaps are filled in. ing firing, the case expands into these cavities and during extraction it needs to squeeze to a smaller size in order to be removed. I call this "chamber bottleneck" and it exerts great effort on the extractor and casing itself. Basically, this is a form of extrusion and it often leaves marks on the fired case.

The tension related with this extraction makes it physically difficult and can force the extractor to slip from the rim. Then the shooter has a real inconvenience. My customer, the owner of this 9mm shotgun, wanted to shoot it again and had large amounts of these 9mm shotshells. Inspection revealed the gun needed anew chamber. New Chamber, Old Flobert Inserts, liners, sub-caliber tubes, chamber mates, and the like have been well known and used for centuries.

Some of these devices are temporary while others are permanent. In the case of this Flobert shotgun, we need a permanent, new chamber. The old, damaged chamber had to be reamed out and an insert with new chamber needed to be fabricated, soldered inside, and chambered for the 9mm shotshell. Pretty easy project, however, I faced one obstacle: There is no available chamber reamer for this shell. I looked everywhere and none were to be found.

I recall a conversation with my apprentice when he asked me how long one should be an apprentice. I replied that in my time in European apprenticeship would normally take several years for learning how to make chamber reamers, heat treat steel, make springs, solder barrels, mix rusting solutions, make tools, and so on. However, with all the tools that are readily available commercially, apprenticeship is much shorter—just push a button on the Brownells website and you are tooled up. Not in this case.

Lets go step-by-step. First, removing the old chamber requires a wellcentered cutter. The diameter of this reamer is not critical since the fit of the insert into the breech should be tight so that the shot pressure is supported primarily by the barrel. I used a 5/8" counterbore reamer with a pilot hole. The pilot needs to be quite long to reach the main bore through the chamber and be very close to the bore diameter. I performed this reaming with a lathe.

Making a reamer requires precision dimensions, a good hi-carbon steel rod, precision turning, milling flutes, hardening/tempering, and sharpening. The major steps I used to make a 9mm shotgun reamer started with a sketch with the reamer dimensions and a corresponding blank turned out of drill rod. From there, I milled six straight flutes. Heat treatment is usual and performed the same as one would treat a spring, but tempered to a bit harder condition.

Sharpening needs to be accurate for providing smooth cutting without deep circular marks, otherwise the new chamber would not be any better than the old one. Preparation of the insert for the new chamber did not present any problems being a simple tube. The front end was straight so as to properly engage with the bottom of the rimmed tunnel. The chamber was then reamed into the soldered insert. After some cleaning and modifying the extractor, the new chamber was complete.

Once the chamber reamer was made, soldering and cutting the chamber was no problem. With anew chamber, the Flobert shotgun was restored and ready for my customer to shoot again. AG