Does Your Glock Have a Picatinny Rail?

Gen 3 21SF Early Military Trial Version

The Glock above is one of my favorite and obscure versions from my collection. It is the first variant of the Gen 3 21SF, released in 2007 and can be considered an experimental model–probably too many made to call it a prototype as it was available to the public for a short while before being quickly phased out. To get the full story, we have to go clear back to the late ’80s when Glock was first coming into the US and realizing the value of government contracts.

Gaston Glock realized quickly that military contract or even law enforcement sales had to be a large focus of the Glock company. The Austrian Armies adoption of the first Gen 17 was a great early success and the income drove further research and development for the company. Mr. Glock always felt that he missed an opportunity when the US help military trials to replace the 1911 as the duty issue handgun but at the time of the trials, he simply was not in a position where he could scale production to the necessary levels should he win the contract.

Upon entering the US market in late 1985, the company decided to focus on the next best thing available: law enforcement contracts. Though there is no official Glock historian to confirm some of the legends, the most common story I’ve read is that the tiny police department of Colby, KS was the first to sign up with Glock pistols–but they were soon followed by an avalanche of agencies shelving their old service revolvers and steel framed semi-autos in favor of the lighter, more reliable Glock design.

The infamous “Miami shootout” spurred the FBI to begin searching for a more powerful handgun cartridge for field duty and they briefly courted the use of 10mm as the standard issue cartridge. While the FBI contract wasn’t nearly as large as the US Army contract could have been, it came out at a time where the Glock company could now take advantage of the bid. However, up until 1990, the Glock company was only making 9mm designs. The R&D department had to go into warp mode to try to get a 10mm handgun off the ground but it proved to be too large (and too powerful) of a cartridge to be contained in the standard Glock model frame. This lead to a tough choice for the company; Either introduce and over-sized gun that was “beefed up” enough to handle the 10mm or sacrifice the double stack design that was one of the main selling points of the Glock over revolvers (or 1911s for that matter). Glock chose option A and began development of what was to become the model 20 on a larger platform.

Since they now had a larger platform standard, it was only natural that a .45 ACP version of the gun be developed to court American’s infatuation with the .45. This became the model 21.

As a side-bar, the FBI quickly gave up on the 10mm cartridge as being too large and too unwieldy for everyday use which led to a collaboration with Smith & Wesson and the development of a shorter 10mm casing that came to be known the “.40 S&W.” In a stroke of irony, Glock was able to quickly launch a version of the model 17 firing the .40 cartridge and steal the FBI contract right from underneath S&W (these were the first models 22 and 23). The further refinement of the 10mm and .45 ACP models 20 and 21 were actually put on hold in order to go full bore on the 22 and 23.

When finally released to the public, sales of the larger frame models were lackluster–especially considering the huge demand for a .45 ACP handgun. The basic problem was the massive size of the grip was simply too large for the average hand. The problem vexed Mr. Glock for years eventually leading to the introduction of the model 36, a single stack .45. But it too, suffered from slow sales mostly due to the smaller capacity (only holding a 6 round mag).

To come full circle, there were rumblings in the mid 2000s that the US Army was growing tired of the Beretta M9 and the 9mm cartridge in general. USSOCOM oversaw the “Joint Combat Pistol” program but procurement stipulations vacillated over design features and continued pushing out deadlines. Still feeling that he had missed a great opportunity by being too late to the 80’s military trials, Ghaston Glock was willing to do whatever necessary to secure a large government contract so the JCP became the impetus needed for Glock to rework the model 21 design. They knew the Army wanted a .45 ACP, with larger capacity, but some of the spec sheets also called for a Picatinny rail on the nose and that controls had to be fully ambidextrous. They also knew that the standard model 21 was too large to emerge victorious from the strenuous military trials. Glock began development but many different versions of a “final” design were completed, then changed, and eventually the JCP program was canceled altogether and the military decided to just keep the M9.

The result of the refinements to the model 21 became the model 21SF (which stands for “Short Frame”) and the final final version was just a standard model 21 with a shorter front to back grip dimension. But for a few lucky collectors, you will still find Picatinny rail, ambidextrous mag release variants out there on the open market as pictured above. The rail design works perfectly, but the ambi-mag release was not up to snuff and Glock quietly replaced a large number of the initial guns with standard right-hand release guns. Even today, they will offer a full replacement with a new Gen4 model if you are willing to send in the ambi version.

And as a collector, I couldn’t be happier that this gun grows more rare with each one that get’s traded in.


Published by That "Glock" Guy

Licensed firearm dealer from Tulsa, OK and an avid Glock collector. This site is born from my hobby of trying to track down rare Glock production models and piece together the early history of America's most popular gun.

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