Engineering terms like “ISO 9000,” “mil-spec,” and “air gauge” don’t really exude that much marketing sizzle when some faceless advertising guru tries to hype a new firearm. But these terms and other professional argot do take on significant meaning for civilian shooters when you take a factory tour through the plant of a Pentagon arms contractor, and find that the same demands for precision and quality control are applied to their line of civilian guns as well.

I caught up with Sabre Defence Industries’ Director of Sales and Marketing, Mike Curlett, following the 2010 SHOT Show, and he was gracious enough to give me a factory tour of their Nashville, TN, manufacturing facility to inspect the company’s lineup of new gas-operated piston XR15 rifles. The XR15 family consists of the M4 and M5 Tactical Piston Carbine as well as the Competition Deluxe Piston rifle.

Early in the tour I learned the true meaning of “mil-spec:” The U.S. government supplies contracted weapons manufacturers with a TDP (Technical Data Package) that specifies all of the critical dimensions for every part of a firearm. “All M16 uppers and lowers are from government mil-spec forgings based upon TDP drawings,” Curlett said.

TDPs are closely guarded secrets that require tight security for reasons of national defense. The author has toured several firearms factories over the past two decades, but none were as tightly controlled as Sabre Defence
Another aspect of Sabre Defence’s manufacturing process is that all raw metal stocks or parts utilized are made in the USA.

One of the quality control devices employed at Sabre Defence is the air gauge, and they use it liberally. Many gun manufacturers use air gauges to check final barrel tolerances, but Curlett said that Sabre Defence employs it between each step in the 10-step AR barrel-manufacturing process.
The air gauge and other measuring devices are employed in the ISO 9000-2008 manufacturing process to check part tolerances to certify that they meet military specs. The not-so-sexy sounding process tracks every barrel made through lot numbers that are etched on the barrels early in the manufacturing process. This process identifies any problems in manufacturing, to allow quick corrections. “All the steel we use comes from the same mill so we can control quality,” Curlett added.

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Engineering terms like “ISO 9000,” “mil-spec,” and “air gauge” don’t really exude that much…