Mainstream handgun cartridges look like a number and a word. The word is where the information is: whether the round is a lengthened parent, a hotter loading in the same dimensions, or a company's own design.

Four suffixes cover most of this set.

Special: the lengthened parent

bulk 38 special and .44 special both mean a case lengthened from an earlier round — the .38 Long Colt and the .44 Russian respectively — loaded a little harder than the parent but nowhere near magnum pressure. Within .38 Special, brand lines add their own words: a search for hornady .38 critical defense points at Hornady's defensive load, and 38 special wadcutter ammo at the target loading rather than a brand at all.

Magnum: lengthened again, kept out of the old gun

357 magnum ammo and 44 rem mag are the Specials stretched a second time and loaded to a pressure the older revolvers were never built for. The extra length is deliberate: it keeps a magnum out of a Special's cylinder while letting the Special drop into a magnum's.

Super and +P: hotter in the same case

.38 super ammo is the exception to the lengthening rule. It shares dimensions with the older .38 ACP and is simply loaded hotter, which is why its headstamp carries a +P marking and why it should never go into a pistol built for the parent round.

A company's name as the designation

357 sig ammo carries Sig Sauer's name because Sig and Federal designed it in 1994 — a .40 S&W case necked down to a 9mm bullet. The name is the registered designation, not a brand of some generic round.

The plain ones

380 rounds and .40 ammo carry no suffix worth decoding: “ACP” marks the Browning pocket-pistol lineage, and “S&W” on the .40 credits the company that shortened the 10mm. Neither has a magnum sibling.

The practical rule

Special fits in Magnum; Magnum does not fit in Special. Super and +P need a gun rated for them. A company name means one specific design. That covers most of the counter.

Cartridge naming varies by manufacturer and era; always match the exact designation or case dimensions stamped on your firearm before ordering ammunition, and confirm current stock and any state shipping restrictions before checkout.