A Matter of Calibre

When calibre is mentioned in regard to firearms, we usually think it’s to do with the size of the projectile. Broadly speaking, this is true. However, there are some different systems for describing cartridges. We will look at some common examples below.

9mm Luger

The European designation is 9 x 19mm, meaning a 9mm bullet seated in a rimless cartridge case 19mm long. (If the cartridge was rimmed, it would be referred to as a 9 x 19R). For this reason, many European firearms simply carry the 9 x 19 designation. The photograph above shows two 9mm Luger cartridges alongside a .22LR cartridge for comparison.

What does +P and +P+ Mean?

Any cartridge with +P or +P+ designation means that it is loaded to a higher pressure than standard, and may not be suitable for your firearm. If you have any doubts as to whether your firearm is compatible with +P ammunition, seek expert advice.

Military Grade 9mm Ammunition

Any cartridge with +P or +P+ designation means that it is loaded to a higher pressure than standard, and may not be suitable for your firearm. If you have any doubts as to whether your firearm is compatible with +P ammunition, seek expert advice.

38 Special

Released by Smith&Wesson in 1899, the .38 Special isn’t really a .38 at all. The bullet diameter is actually .357ʺ.  Originally known as the .38 Smith&Wesson Special, it is a rimmed cartridge originally intended for use in revolvers, but now can also be found in automatic pistols as well as rifles.

In 1935, Smith&Wesson released the .357 Magnum, as many law enforcement agencies felt that the .38Special lacked stopping power. The .357 Magnum uses the same diameter bullet as the .38 Special; however, the case has been lengthened slightly. This is to stop inadvertent chambering of a .357 Magnum round in a .38 Special revolver. However, a .357 Magnum revolver will quite happily chamber and fire a .38 Special. The photograph below shows a .38 Special (L) alongside a .357 Magnum.

Shotgun Cartridges

Shotgun relate to the diameter of a lead ball. Therefore, a 12 gauge shotgun shell is the diameter of a lead ball weighing 12 to the pound. A 20 gauge shell is the diameter of a lead ball weighing 20 to the pound, etc. The exception is the .410 gauge. The .410 shotgun is .410ʺ in diameter.

Shot size is given a number. The bigger the number, the smaller the size. In the photo above, the 12gauge shell is loaded with No. 7½ shot. The 20 gauge shell beside it is loaded with No. 4 shot. Larger size shot are given letter or number designations.  (E.g. SG, which is an English designation, is the equivalent to American 00)

Other descriptors for shotgun cartridges are length of the case (e.g. 2¾ʺ or 3ʺ), and sometimes the weight of shot carried (Usually in grams, sometimes in ounces).  Older ammunition sometimes carried a “dram equivalent”. A dram was an Imperial measurement, with a standard 12 gauge 2¾ʺ load being charged with 3 drams of black powder. When smokeless powder came into vogue, many manufacturers used the dram equivalent so shooters knew how powerful the load was.

Safety considerations for Shotgunners

As can be seen from the previous photograph, there is not a lot of difference between 12 and 20 gauge shotgun shells. Accidents have occurred over the years when a 20 gauge shell has been stuck in a 12 gauge gun barrel, then having a 12 gauge shell loaded into a seemingly empty gun,

3ʺ shells should only be used in guns marked accordingly. A 2¾ʺ shell can be used in a 3ʺ chambered gun, but not the other way around.

Proof Marks

Older shotguns may only be proofed for use with black powder. If in doubt, seek expert advice before using modern smokeless cartridges in an old gun.

Steel Shot

Many jurisdictions have mandated the use of steel shot for hunting. As steel is much harder than lead, it should only be used in guns proofed for steel shot.

Reading the Fine Print

Whether in the owner’s manual or on the ammunition packaging, in shooting, as in life in general, it always pays to read the fine print.

Until next time, have a happy and safe shoot!

References: Cartridges of the World 13^th Edition

                   Winchester Ammunition Catalogue

Researched and written By Anthony Mitchell

Back in 1907, the British Army adopted the Short, Magazine, Lee-Enfield (SMLE) rifle as standard issue for all branches of the armed forces. Previously, there were different styles of rifles and carbines for different branches of the service. The new rifle was shorter and handier than the long Lee-Enfield it replaced.

The military doctrine of the day placed emphasis on the combat use of the bayonet, and the feeling was that the shorter rifle required a longer bayonet to place the British infantryman on an equal footing with the enemy.

Various designs were contemplated, but the pattern selected was based on the bayonet used by the Imperial Japanese Army with the Arisaka rifle.

Over 5 million P1907 bayonets were made during World War 1 alone, with many manufactured by Wilkinson Sword. The P1907 bayonet coupled with the SMLE was used by British and Commonwealth forces during both world wars.

The photo below shows the bayonet in its leather scabbard

During the 1920’s, the SMLE was designated the “Rifle No. 1 Mk III*”. The Pattern 1907 bayonet stayed the same.

Australia manufactured the SMLE and Pattern 1907 bayonet until the 1950’s, so the Pattern 1907 bayonet is relatively common out here. The photograph below is a display in the Lithgow Small Arms Factory Museum.  The display shows SMLE‘s and P1907 bayonets from every year of manufacture.

Until next time, have a happy shoot

References: The Lee-Enfield by Ian Skennerton and various internet sources