The Venerable .22 Rimfire

The Venerable .22 Rimfire      

By Paul Evancoe

Many of us began our shooting experience with a .22 rifle. That’s because the .22 rimfire cartridge is the most prolific round with the most varied chamberings of any cartridge ever fielded. The .22 rimfire cartridge has a rich history beginning in 1845 when Frenchman, Louis-Nicolas Flobert invented the first rimfire metallic cartridge named the 6mm Flobert cartridge (aka: the .22 BB Cap). The .22 BB Cap (BB standing for Bulleted Breech Cap)was little more than a breech-style rimfire percussion cap with a case outside diameter measuring 6mm and a 5.6mm (.22 cal) 16 grain lead ball inserted into the top opening. While the invention of the first modern percussion ignitioncapis credited to Scottish Presbyterian clergyman, AlexanderForsyth in 1807, Flobert turned it into a metallic cartridge.

The cap bodies were simply small thimble-shaped cups with a base rim flange that were die-formed out of thin iron, pewter, or copper sheet (today’s center fire primer caps are formed out of aluminum).  A small amount of pressure-sensitive chemical explosive, called an initiator, was cast inside the cap base. Typical initiators used during that era were mercury fulminate or potassium chlorate, in combination with oxidizers. As a group, these initiating compounds were called fulminating powders, or simply, fulminate. Today it is known as the “primer.”

Using this fulminated-base cap design as a crude cartridge meant the firing pin could strike the cap’s bottom outside face at any location to fire the cartridge. Since the cap’s base rim (flange) diameter was already small (6.9 mm), with very thin metal across its center, Flobert designed a firing pin strike point to impact along the cap’s base rim where the metal was folded to create the flange. Striking this thicker rim area all but eliminated the likelihood of puncture that could vent combustion gas rearward towards the shooter. Thus, the rimfire cartridge was born. So now you know – It’s called rimfire ammunitionbecause the gun’s firing pin strikes and crushes a small notch into the cartridge base’s rim to ignite the primer (fulminate), and that fires the cartridge. 

These first Flobert .22 BB cartridges did not contain any propellant powder. The onlypropellant was the fulminate cast into the internal base of the BB cap. Although crude by today’s ammunition designs, the Flobert cartridge led to the elimination of muzzle loading and cap and ball firearms by combining a percussion cap (that later included a pre-measured powder charge), and a bullet in a single self-contained, easily loaded, weather resistant cartridge. 

Flobert made use of his new metallic cartridge ammunition in what he called “parlor guns.”These heavy barreled rifles and pistols, many with ornately engraved metal work and relief carved furniture (stocks and grips), were designed for in-home target shooting. In the mid-19th century it was fashionable for wealthy Europeans to have a dedicated shooting parlor, or shooting gallery inside their homes. Flobert’s new ammunition fired by his parlor guns answered that market. 

Prior to the 6 mm Flobert cartridge, a typical “cartridge” consisted of a premeasured quantity of black powderwrapped together with a ball, in a tightly rolled paper cylinder or small cylindrically-shaped cloth bag, which also acted as wadding (gas check).This fragile cartridge was either breech loaded or muzzle loaded (depending on the firearm’s design), and ignited by a percussion cap that was separately     attached to a cap nipple (touch hole). While far faster than muzzle loading individual components (powder, wad, ball), this delicate paper or cloth cartridge was neither weather resistant, nor utilitarian. 

In 1888, the .22 BB Cap Flobert introduced in 1845 was improved and became the .22 CB Cap(CB stands for conical bullet).  The .22 CB Cap was loaded with a lead-cast .22 caliber conical bullet instead of a ball. It also became slightly more powerful than its predecessor when a few grains of black powder were added inside the percussion cap cavity to boost bullet velocity from the BB’s 400ft/s to CB’s 700 ft/s. Even so, both the BB and CB cartridges (still available today) are called 6mm Flobert,and for all practical purposes are considered the same cartridge. 

Unique to that point in history, Flobert designed a distinctive bullet shape for his cartridge using what is known as a “heeled” bullet design.This was necessary because the bullet and the cartridge case outside diameter are the same. Therefore, Flobert narrowed the bullet’s base to form a ‘heel” or “shoe-like” shape so it could be inserted into the cartridge case. 

Thus, rimfire ammunition got its start and continued to evolve. In 1857, Smith & Wesson developed the .22 Short for specific chambering in their newest revolver. The .22 Short used a lengthened CB rimfire cartridge case loaded with 4 grains of black powder that propelled a 29-grain lead cast conical “heeled” bullet. This success in popularity and performance led to the 1871 debut of the .22 Long.  

The .22 Long used the same 29-grain bullet as the .22 short but it employed a longer cartridge case that provided the needed space for 5 grains of black powder, which increased bullet velocity to near sonic speed.This was followed by the .22 Extra Long in 1880, which was designed primarily for use in bolt-action rifles. With a case longer than the .22 Long and a heavier 40-grain outside lubricated conical lead bullet, the Extra Long was loaded with 6 gr of black powder.

Building upon these many successes, the .22 Rimfire continued to morph. In 1887, U.S. arms manufacturer, J. Stevens Arms & Tool Company introduced today’s favorite .22 Long Rifle cartridge (22LR). Stevens brilliantly combined the casing of the .22 Long with the 40-grain bullet of the .22 Extra Long and loaded it with smokeless powder. This component marriage gave the 22LR a longer overall length, a higher muzzle velocity and superior performance for small game hunting, plinking and competition shooting. These enhancements also improved 22LR performance and popularity to the point its success doomed both the .22 Long and .22 Extra Long cartridges to obscurity. 

In 1890, Winchester introduced its M1890 slide rifle (pump action) that fired Winchester’s latest .22 rimfire ammunition improvement: the .22 Winchester Rimfire, or .22WRF. This ammunition employed a slightly larger diameter cartridge case than the .22LR and a flat base flat-nose bullet, making it ideal for use in pump rifles with tubular magazines. The .22 WRF bullet also differed from its .22 rimfire predecessors’ outside-lubricated grooved bullets (used in the .22 Short, Long, LR, and Extra Long), by using inside-lubricated bullets which protected the lubrication from dirt contamination. While demonstrably less accurate than the .22LR it possessed a notable improvement in killing power. 

But the .22 WRF met with obsolescence just prior to WW-II as smokeless rifle propellants improved so significantly they replaced black powder and nitro-cellulose propellants. By loading this new high velocity smokeless propellant in the .22 LR cartridge, its bullet velocity soared into the 1,300 to 1,500 ft/sec range, trumping the .22WRF with increased power at a far cheaper cost per round. 

Winchester debuted the next major improvement in .22 rimfire ammunition in 1959 with their.22 Winchester Magnum Rifle ammunition, or .22WMR. The WMR cartridge case is essentially a lengthened version of the older WRF cartridge case with a jacketed bullet. The WMR is offered in a range of 30 to 40 grain unlubricated jacketed (or plated) bullets. While comparable in bullet weight to the .22 Long Rifle, the WMR rounds fly faster, flatter and farther and carry far superior kinetic energy at all ranges. For example, WMR bullet velocities using a 30-grain bullet can easily exceed 2,300 ft/sec, and 1,875 ft/sec using a heavier 40-grain bullet when fired from a rifle. 

Because of the WMR’s larger case diameter and greater length, a .22WMR round will not chamber in a firearm chambered for any other .22 cartridge. However, the reverse is possible and if fired, the resulting hot high-pressure gas venting around the smaller .22 cartridge case, can be very dangerous to the shooter’s face and eyes. 

Remarkably, in terms of ammunition quantity sold over the last 150 years, .22 Long Rifle far exceeds the popularity of any other commonly used ammunition on planet Earth. Some of the reasons are its low recoil, low cost (per round), and the large variety of rifles and handguns chambered to fire it. However, .22 LR ammunition has experienced sporadic availability issues over the past, resulting from the government’s tightening of firearms purchase and ownership regulations. 

For those who experienced the threatening on again/off again times of firearms regulation – especially leading up to the 2006, through 2016 House, Senate and Presidential elections, you may recall those times when store ammunition shelves were sold out and ammunition hoarding became the norm. Today .22-rimfire ammunition is abundantly available, but that availability will again become threatened depending upon which political party is in power. Therefore we should anticipate future ammunition shortages, at which time the political power changes hands. During such times dating back to the early 1900s, reloading centerfire ammunition has always been a fallback to traverse ever-restrictive firearms and ammunition regulations. But today, reloading .22 rimfire brass has mostly been discounted as the impossible dream. 

Is reloading .22 rimfire worth it? You be the judge. If history repeats itself, there will be future ammunition shortages. Having this inexpensive reloading capability in your hip pocket is insurance from tyranny.   This article is intended for informational purposes only. Do not attempt any of actions without professional guidance

This article appeared in July Small Arms Review HERE