Story and photo by Guy J. Sagi

On Feb. 28, 1935, DuPont scientist Wallace Carothers made a discovery that forever altered the composition of everyday items. His Nylon 66 fibers were busy brushing teeth nationwide by 1938, although he committed suicide in 1937 and never witnessed his contribution’s contribution to dental hygiene. His masterpiece gained even more sex appeal in 1940, when the less-expensive alternative replaced silk in women’s stockings, giving budget-strapped gals the ability to bait sailors with polymer-coated gams. There are those who claim synthetic-framed guns aren’t even shore-leave alluring, but there’s no denying the lineage.

Nylon 66’s ability to mix with different compounds—each imparting a different characteristic or color—saw the substance pressed into deadly serious duty during World War II as tire reinforcement, rope, flak vests, parachutes and more. Then mystery brews evolved, and the derivatives today serve as car heat shields, permanently lubricated nylon bolts and much more.

More than 30 years ago the material was introduced in firearm frames. There’s still a lot of misinformation about the materials and quirks of synthetic guns, so I asked a few experts to share their knowledge.

Two Basic Brews

It all can be boiled down to two basic brews. DuPont holds the patent for Nylon 66 (Zytel). Nylon 6 (trade name Perlon, Capron and others) was developed in 1938 by a different process to avoid intellectual property infringement, but it still exhibits many of the same characteristics. There are significant differences, however. The latter melts at 428 degrees Fahrenheit, compared to 509 degrees. Nylon 66 weathers exposure to damaging sunlight better than the easier pigmented Nylon 6, but the latter loses color faster. The molecular structures may be widely known, but the secrecy surrounding Coca Cola’s original formula pales in comparison to the security surrounding the firearm industry’s polymer additives.

Even when everything else is equal, there are other variables manufacturers tailor for unique looks and performance. Final gloss changes when molded at a different heat, for example. Add a 30-percent glass-fiber filling and strength increases by up to 200 percent. Unfortunately, the resulting material is extremely abrasive, potentially wearing out factory molds prematurely and galling gunmetal—unless you’ve found the kind of secret sauce that works, it’ easy to understand the need for secrecy.

Polymer Wear-In?

Heat from the firearm being shot is another facet manufacturers must consider. “Polymer frames are manufactured under tremendous heat and pressure during the injection-mold process, and subsequent after-the-fact applied heat will cause minor resting of the material,” according to Dave Borges, CEO and co-founder of Polymer80—a producer of polymer AR-15 uppers and lowers. “In terms of a pistol frame, the tip of the barrel is where specific heat is applied, although the barrel is not touching the frame. This heat is predictable and therefore the injection mold is designed to manufacture the frame with the ultimate relaxation of the material in mind…It does not impact performance or accuracy.” It takes 500 to 1,000 rounds for a handgun’s polymer to “relax.”

Despite the challenges, Remington first introduced shooters to synthetics back in 1959 with the unimaginatively named Nylon 66 Autoloader. The stocks were made of Zytel and the rifles digested .22 rimfire. The last Nylon 66 was produced in 1985, with a total of 987,949 made. Heckler & Koch’s 1970 introduction of the polymer-framed, blowback-operated VP70 chambered in 9 mm really started the revolution. The reception was lukewarm, though, and sales limped along until production ended in 1989.
Meanwhile, Gaston Glock pressed his engineering knowledge into service in 1982 to create the recoil-operated Glock 17. It won an Austrian military 9 mm handgun contract, other countries followed suit and in 1986 “plastic guns” invaded America.

Keeping the Secret

Our efforts to uncover the recipe proved fruitless. Chad Dyer, marketing manager for Springfield Armory said, “The XD/XDM frames are a ‘filled’ polymer, but it is a proprietary process and composition.” Borges even apologetically begged off a photo request with, “Unfortunately, we can’t do that. Our producer keeps everything top secret and it would be a breach of contract to take pictures. Sorry…”

There were, however, discoveries. Some surmise color is a lifespan concern, but Dyer explained, “None of the color options we offer negatively affect the strength of the frame.” Borges issued a more blanket statement with, “Colorants don’t impact the longevity or rigidity.”

How Long Will Polymer Handguns Last

We still don’t precisely know, but all the experts agree prolonged exposure to UV radiation (usually sunlight) will degrade the frame after many years. For an instant disaster, however, Borges cautioned, “Acetone is the single most potent chemical that will nearly destroy any polymer components. While gunsmiths use it for cleaning metal components, you shouldn’t even get a drop of it near polymers.”

It may not have the same sex appeal as the world’s first nylons, but modern shooters should find a different kind of appeal in Dyer’s proclamation that, “The polymer frame will last virtually forever, including the rear frame rails on the XD/XDM line, as they are self-lubricating and virtually wear free. I have never seen the rear frame rails wear to an unserviceable condition,” he said.