Cartridges and calibers: a practical comparison

Caliber, cartridge and bullet: three different things

Caliber often refers to an approximate bore or bullet diameter. Cartridge is the complete ammunition designation: it describes a particular family with its own case and chamber requirements. Bullet is the projectile, not the entire round. A .22 LR cartridge and a .223 Remington cartridge have roughly similar diameter projectiles, yet belong to very different systems. Shared digits do not establish compatibility.

Rimfire ammunition places priming compound in the case rim; centerfire ammunition uses a primer in the center of the base. Both include a case and propellant. A grain is a unit of mass, not a type of powder: bullet weight printed as “124 gr” is not the propellant charge. Box velocity is a result from a stated test setup and may differ in another firearm.

Reference: SAAMI · Complete technical glossary

.22 LR and .22 WMR: inexpensive practice and small game

For a household that already owns a lawful sporting firearm, .22 LR can make regular range practice relatively affordable. The cartridge is used in rifles and handguns; the action and specific ammunition still affect reliability and the experience. .22 WMR is a distinct chambering, not a “magnum setting” on a .22 LR firearm. Some revolvers have manufacturer-supplied interchangeable cylinders, but that is a model-specific arrangement rather than permission to mix ammunition.

Small-game hunting is a skill and a regulated activity, not an automatic food plan. Species identification, access to permitted land, seasons, humane harvest and food handling all matter. In Florida, for example, rimfire rifles are not a legal method of taking deer. Lightweight ammunition does not remove those limits or make large-game use appropriate.

Reference: CCI · Rimfire cartridge comparison · Florida FWC · Methods of taking game

Handgun cartridges: names, platforms and real tradeoffs

A comfortable range firearm depends on grip fit, overall mass, controls and the particular load. A compact pistol is easy to store but may have a less forgiving grip and sight picture than a larger sporting model. It is therefore misleading to promise that a cartridge is “easy for everyone” or rank the whole experience by bullet diameter alone.

Suffixes matter. +P denotes a higher-pressure designation for certain standardized cartridges; it is not an upgrade for any firearm bearing the base name. +P+ is not a single universal SAAMI pressure standard. The firearm manufacturer must authorize the exact ammunition category. Keep ordinary and special-pressure products distinctly labelled rather than combining loose rounds because the headstamps look similar.

Reference: SAAMI · Equivalent cartridge names · SAAMI · Cartridge compatibility FAQ

.223, 5.56 and the three very different “7.62” names

SAAMI explains that .223 Remington ammunition can generally be used in a manufacturer-confirmed military-specification 5.56 chamber, while 5.56 ammunition should not be assumed safe in a .223 Remington chamber. A .223 Wylde marking refers to a chamber design, not a separate cartridge on the shelf; consult that firearm’s manual. The useful lesson is specific compatibility, not an improvised fit test.

A number such as “7.62” gives too little information to choose ammunition. Case length, shape, chamber standards and intended loading differ. Likewise, “.308 and NATO are the same” is too broad for every firearm, including older examples. Rifle cartridges also tend to add ammunition bulk and report compared with rimfire. Hunting suitability depends on the species, projectile, firearm and law; there is no universal caliber that solves every outdoor task.

Reference: SAAMI · Cartridge compatibility FAQ · SAAMI · Equivalent cartridge names

12 and 20 gauge: read the whole shotshell label

Gauge is a historical bore-size system, not a caliber in millimeters. Within this system 12 gauge is a larger bore than 20 gauge; .410 bore is an exception named by bore diameter. A shotgun may use shot, a group of pellets, or a slug, a single projectile. Those are different load types within the shotgun family, not different names for the firearm.

Clay sports and bird hunting often use shotshells selected for the rules of that activity. Bigger gauge, heavier payload or “magnum” branding does not automatically mean better results. Firearm fit, total weight and the particular load affect recoil. Check both firearm and ammunition instructions; a shell slipping into an opening does not prove it belongs there.

Reference: Winchester · Reading a box of shotshells

Build a comparison that answers your actual question

For a sporting purchase, write down the activity first: affordable paper-target practice, a particular licensed hunting activity or an established club discipline. Compare the cost of routine ammunition, range fees, instruction, secure storage and maintenance as well as the firearm. Availability in your area matters more than an attractive specification from a product you cannot regularly obtain.

• Record the full chamber designation, exact model and manufacturer-approved ammunition categories.
• Compare prices per round within the same cartridge and intended sporting load type.
• Keep product codes and lot numbers when you buy; they make recall checks possible.
• Reject simple “bigger is better” claims. Cartridge names alone do not describe reliability, accuracy or suitability.
• Use the cartridge guide alongside the ammunition-storage guide; identification and condition are separate checks.

For preparedness, preserve the sporting equipment you already understand before adding unfamiliar systems. A labeled, modest inventory that remains secure, dry and identifiable is easier to manage than assorted loose ammunition. Skills, lawful access and realistic expectations give the equipment a purpose; the cartridge label alone does not provide one.