Today, the portable Meals Ready to Eat (MRE) consumed by American ground troops come in packages that are easy to open. In times past, the rations carried by a soldier or Marine were enclosed inside steel cans. The P-38 pocket can opener of the early World War II era was the solution to opening a can of food and chowing down. Some soldiers and Marines rate the P-38 as one of the handiest inventions ever issued to troops.

While the U.S. armed forces have not issued any P-38s since the mid-1980s, some troops still carry them today. Some have been passed from one generation to the next. Many are part of collections of memorabilia belonging to veterans of past wars.

In 1942, the Subsistence Research Laboratory of Chicago was charged with developing a can opener. The Army’s K-ration came with a key opening system, but soldiers disliked it, and their complaints caused the Quartermaster Corps to seek an alternative. The idea was to design a device that was cheaper to make and faster to use than a standard can opener; yet was small and easily carried. The result was a small, folding can opener, the P-38. It was hinged and was just 1 and 1/2 inches long with a hole in one end. The hole was to intended for wire or string to pass through to enable a soldier to drop the can opener into boiling water for cleaning in the field. However, it also worked perfectly for hanging the P-38 on a dog tag chain.

The P-38 was first issued in 1943 as part of a ration item known as the Hospital Five-in-One. It became the standard issue item with the G-ration in June 1944. Subsequently, it was issued along with the more widely used C-Ration, which remained in inventory in the postwar era. Finally, the opener was issued in all Army field rations. The Marines picked it up and dubbed it the “John Wayne,” apparently because of its toughness or because the actor demonstrated it in a training film.

Soldiers and Marines didn’t really need to watch the film, though, because written instructions and a drawing printed on the can opener’s paper pack showed how easy it was to use.

Although “Opener, Can, Hand, Folding” is its official Army nomenclature, it soon acquired the popular name P-38. Historians disagree as to which of three theories explains the moniker. One is that soldiers called it the P-38 because it could open a can faster than the P-38 Lightning fighter plane could fly. A more likely explanation is that the “38” comes from the length of the can opener, which is 38 millimeters (or 1 1/2 inches). It also is possible that “38” was the number of punches (a “P” word) it took to open a ration can. All experts agree that P-38 did not derive its name from the Walther P-38 pistol used by the German military in World War II.

A Real Keeper

The P-38 was designed to be disposable. The Army assumed soldiers would throw them away after opening their ration cans and began putting one P-38 in every individual ration accessory pack.

But no smart soldier ever discarded his P-38. There might always arise a situation in which he might be unable to eat because he did not have a can opener. Once the Army realized that most soldiers were saving the device, it started placing fewer of them in each case of C “rats.”

Although soldiers kept the P-38 to open their rations, they also retained it because it was an invaluable field tool. According to an article by Maj. Renita Foster in the Pentagon’s newspaper in 1986, the P-38 could clean muddy boots, screw screws, open letters, strip wires, trim threads on uniforms, and sharpen pencils. The P-38 can be used to open cardboard boxes, including the cartons containing Meals Ready to Eat. Some claim that the P-38 could be used to set the points on a car engine, because the thickness of the steel was just right for the point gap.

Many a soldier hung his P-38 with his dog tags around his neck. The P-38 disappeared as an issue item in the Army, but some still carry them today, often on a key ring after acquiring it from a family member or friend or purchasing it.

The Army also developed the P-51 can opener (again, with an airplane namesake, the P-51 Mustang fighter). This was a big brother of the original, so to speak, about twice the size of a P-38 and easier to use. Mess hall cooks used it to open field ration metal pre-cooled meal trays. The P-51 can opener is fully 2 inches long, and the increased length provides greater leverage when opening cans.

Several companies are producing versions of the P-38 and P-51 can openers for civilian purchasers today.

Co-author: Fred L. Borch