Can a firearm fire different caliber bullets?

Posted by Veronica Gene Ariño on May 1st 2020

Can a firearm fire different caliber bullets?

Some calibers are interchangeable, but if the wrong bullet is chambered in a gun, the damage is devastating and has lead to the deaths of more than a few people when fired.

To get a better understanding, let us first define what exactly is caliber?

The caliber of a cartridge is the measurement of the diameter of the slug (or projectile) also known as the bullet. In some situations, the bullet casing will be wider than the slug, but the caliber specifically describes the width of the slug portion. Caliber does not refer to the length of the casing or power of the bullet. Simply the diameter of the bullet.

However, to set an example, the .223 Remington and 5.56×45mm NATO cartridges are very similar to each other but with one very important difference. The difference between them is the chamber pressure they can handle. The cases tend to have similar capacity when measured, although the shoulder profile and neck length are not the same. 5.56 NATO cartridge cases tend to be slightly thicker to accommodate higher chamber pressures. When hand loaded, care is taken to look for pressure signs as 5.56 NATO cases may produce higher pressures with the same type of powder and bullet as compared to the .223 Remington cases. The .223 Remington chambers are smaller overall and have a shorter leade with a steeper angle than 5.56mm chambers.

This means that a .223 Remington ammunition may be shot safely in a 5.56mm chamber, but DO NOT shoot 5.56mm ammunition in a rifle with a .223 Remington chamber as it may lead you to a life-threatening accident.

the problem of using 556 in a 223

The Danger of Using Wrong Ammunition.

If you do not match the ammunition to the firearm, the cartridge could become lodged, explode, and cause serious injury to the shooter or a bystander. For safety purposes, you should use only ammunition of the caliber or gauge designated by the firearm manufacturer for use in that firearm. Markings indicating the correct caliber or gauge of ammunition to be used in a firearm are usually found on the firearm’s barrel, frame or receiver.

As mentioned above, some calibers are interchangeable. Let’s be clear about that, cartridge designations are normally highly specific and individual. Each designation will usually refer to a single cartridge having unique dimensions or ballistics. There are, however, occasions when this is not the case.

The safest example would be when ammunition manufacturers use 2 or more different names to refer to the exact same cartridge. This actually arises fairly frequently with cartridges that are sold or manufactured in both the United States and Europe.

Cartridges that have been adopted or manufactured by many different nations over a long period may also pick up a variety of designations. Such examples are 9mm Luger; .458 Win mag in the .458 Lott; Smith & Wesson Model 48 and 22 Magnum; and Glock 20 and 10mm Auto. These are just a few of the examples of multi-caliber guns/interchangeable bullet calibers.

Life-Saving tips:

  • Check the headstamp on the ammunition to confirm that it matches the caliber or gauge markings placed on the firearm. Some types of ammunition do not have markings on the headstamp of the cartridge. In that case, check the original ammunition packaging to determine its caliber.
  • If you have any doubts about the caliber of the ammunition, you should NOT use the ammunition until you have it examined by a qualified person who can determine its caliber. Remember just because a round of ammunition can fit into a firearm’s chamber, barrel or action does not mean it is safe to use that ammunition in the firearm.
  • If the caliber or gauge is not clearly marked on the firearm, or if it appears the original markings on the firearm have been altered or modified in any way, DO NOT use the firearm as serious injury or death could result to the user and or bystanders, as well as damage to the firearm. Have the firearm inspected by a gunsmith to determine what cartridge it is intended to fire.

the wrong bullet in the chamber

A short guide on the different common types of caliber:

  • .22LR - Small round for long rifles or pistols. These can be used for defense, but they aren't much above pellet guns.
  • 9mm - The 9mm is great for the range or self-defense. They have enough power to penetrate at close range, but still easy to fire with little recoil.
  • .38 Special - This bullet is bigger and has more power behind it than a 9mm. The 38 special is mainly seen in revolvers. Also, the same diameter as the .357 magnum, but the .357 magnum is longer. The .38 Special case length is roughly 1.15 inches, while .357 Magnum is 1.29 inches, so be sure to use it in a gun designed for it. There is also the new round .357 Sig which has a faster cartridge but has only 506 foot-pounds of muzzle energy compared to the .357 SIG that has lower speeds but muzzle energy of 539 foot-pounds. Among these 3, .38 special has the lowest muzzle energy based on the length of these cartridges which makes it the shortest. The more gun powder it can hold makes it even more powerful. Agencies often fire 38 Specials from their .357 Magnum revolver. This saves money, and the 38 special has less recoil. Be sure that the manufacturer supports firing 38 Specials from their .357 revolvers before attempting to do so.
  • .223 and .308 – These are seen in modern rifles and are great fun at the range. They also can be used for defense, but the guns firing these rounds are larger which makes sense since the bullet is larger.
  • 12 Gauge – This is a shotgun round and is the most common type. There is also 20 gauge which is smaller and 10 gauge which is bigger. Shotgun rounds are used primarily for hunting.

Keep your firearm and ammunition in a separate dedicated case.

Now that we know what danger it could bring us when using wrong ammunition, make sure to keep it off the hands of someone who might not know that yet. Cedar Mill Fine Firearms will take care of that for you. We have just the perfect cases available to choose from for different types of guns to keep you and your guns safe and secured. So, hurry up and catch our best deals waiting for you!