The letter began: “Having recently completed reading Daniel Sweeney’s excellent article ‘When America Was Last in the Arms Race’ (Spring 1995), I had to chuckle when I turned to the … picture of two workers operating a propellant cutter at a Du Pont factory during World War I. Immediately I wondered if this picture should have been featured in your ‘They’re Still There’ section!”

The letter’s writer, Jason Burkett, of Olin Ordnance, went on to explain that one of Olin’s subcontractors, Hercules Aerospace, was still using machines just like the one in that picture to manufacture explosives for, among other weapons, the guns on the Abrams M1A1 main battle tank. Mr. Burkett said he’d try to help me get to see those machines. Just then Hercules Aerospace happened to be bought by a direct competitor of Mr. Burkett’s, Alliant Techsystems, but the people at Alliant proved happy to let me visit—provided I understood that no flash photographs could be taken; a flash would trigger sprinklers that would drench the building.

My destination: the Radford Army Ammunition Plant, in the hills west of Roanoke, Virginia. Arriving there over the crest of a hill through lush fall foliage, I found before me a small, isolated city. In the office of Thomas Starnes, program manager for the plant and the man in charge of the propellant-making machines, I climbed into protective shoes, flame-retardant coveralls, safety glasses, and a hardhat, and we headed out.

As we drove down between brick industrial buildings, aluminum sheds, and cinder-block houses, over railroad tracks and under crisscrossing overhead pipes and ducts and power lines, Starnes said, “It really is a small city here, on more than four thousand acres, with power houses, sewage treatment facilities, a hospital up there on the left, and a fire station.” Pointing at one jumble of buildings, he said, “Those are the acid-area facilities over there.”

We walked into a one-story shedlike building whose main room contained nine machines like the one in the old photograph. The air was heavy with a sharp ether smell and rang with the noise of two of the machines running, sucking in strands of propellant from barrels in front of them to press and die-cut them into useful form. The strands, about an inch across, looked like fresh noodles, but with the hard texture of untouched Bazooka bubble gum.

The front of each machine is a door. Starnes swung open the door of one that wasn’t running to reveal its fairly simple, if very precisely calibrated, workings: The door holds the dies through which the strands of propellant feed, and it shuts against a blade that cuts them into exact lengths.

“When the door closes and the dies ride up against the cutting blades,” Starnes explained, “their movements are coordinated through the gears on either side of the door hinge, which connect when the door shuts. Those gears are fiberglass, so that they’ll strip easily in case of emergency. That’s one of the few changes since the machines came in when the plant was built in 1941. Almost the only things that have changed on these machines are for safety.” Understandable, when the product that leaves by the carload is the stuff that makes Sidewinders, M16’s, and tanks as deadly as possible.

He led me to one machine where the finished propellant pouring out the chute on the side looked like grains of gray sand. “That’s shotgun powder,” he said. “But over there you see stock for a 155-millimeter howitzer; it’s two and a half inches long. We make probably a hundred different cuts of propellant, and these old machines churn it all out with very little variability. You can see that for yourself.” He showed me a graph. “You see, the coefficient of variability stays within six- or seven-tenths of a percent.”

And how old are the machines? “They were here when the plant opened, in 1941,” Starnes answered. “I believe they were new then.” If they were, they hadn’t changed much from the machine at least thirty years older in our photograph. Plates on them identify them as made by the McKiernanTerry Corporation, of Dover, New Jersey, near the Picatinny Arsenal. “We have eight buildings full of these here, maybe seventy-five machines in all. And all they need is to have the cutting heads changed out every now and then. And an occasional paint job.”

We stepped back out into the small military-industrial complex, and looking around, Starnes said to me: “You know, the most amazing thing about this plant, to me, is that they got this entire place up and manufacturing propellant in well under a year. That impresses me.”

And it was built so well that it’s making propellant on the same machines half a century later, for some of the most advanced weapons in the world. That impresses me.