Glock Model 20 10mm Auto Pistol


by Jeff Quinn

Photography by Jeff Quinn & Boge Quinn

October 26th, 2005




The 10mm auto cartridge is a great idea that just never really caught on like it should have with American shooters. Back in the early nineteen-eighties, it seemed to be off to a real good start. It had the blessings of the great defensive handgun  guru of the time, Colonel Jeff Cooper. He regarded it as superlative to his beloved .45 ACP cartridge, and stated as much loudly and often, in person and in print. The first auto pistols chambered for the cartridge were based on the Czech CZ-75, a very good design, and the pistols were produced by Dornaus and Dixon, who called the new pistol the Bren Ten. However, the new guns were plagued by a few problems, mainly the lack of magazines. I remember well reading every word that I could about the new pistol and cartridge, but being young, newly married, and broke, reading about it was the best that I could do. Colt and Smith & Wesson chambered pistols for the new cartridge, as have some others, and the Bren Ten was even carried every week of the first season by Don Johnson, the star of the new hit TV series, Miami Vice. Factory ammo energy figures were impressive for an auto pistol. The energy figures for the 10mm showed the cartridge to be more powerful than either the .45 ACP or the .357 Magnum. The FBI even adopted the S&W handgun chambered for the 10mm Auto. It looked like it was off to a stellar beginning. Why it never achieved much popularity is somewhat of a mystery to me. It certainly wasnít the forty-caliber bullet, as the less powerful .40 S&W cartridge is enormously popular. Recoil could have been a factor, as it can be a bit stiff with the heaviest loads. In the right handgun, however, the 10mm is not hard to control at all, and magnum revolver cartridges are more popular than ever. 

One 10mm handgun that has achieved somewhat of a cult following is the Glock Model 20, which is the subject of this review. The Glock 20 is perhaps the most controllable 10mm pistol yet developed, if the gun fitís the shooterís hand. The exterior dimensions of the 20 are the same as the .45 ACP chambered Glock 21. It works very well for a shooter with medium to large hands. Small-handed shooters need not apply. That is one reason that the .40 S&W became much more popular than the full-sized 10mm auto. Beginning in the late 1980s and ever since, police forces at all levels of government have been actively recruiting women and minorities into their ranks, perhaps to achieve a more touchy-feely police force, I donít know. Most women and many minorities are of smaller stature than the average white police officer of years past, when police administrators wanted big, strong officers on the beat. These smaller new recruits usually come equipped with smaller hands. Police administrators wanted a service handgun that would be a one-size-fits-all proposition, and the .40 S&W will fit into a smaller weapon. It also has less recoil than does the big ten.  However, the Glock Model 20 is very good at absorbing that extra recoil. The 10mm in the Glock 20 recoils almost straight back, without excessive muzzle jump, and is an excellent platform from which to launch the full sized 10mm cartridge.

The Glock pistol operates from a locked breech that utilizes the ejection port as the rear lockup point. That feature, along with some other interesting design features of the Glock places the gun low in the hand, effectively reducing muzzle jump. It works and works very well at reducing the felt recoil of the big ten.  The Safe-Action trigger pull is neither like a single action nor a double action trigger pull. It is somewhat in between.  It is quite easy to get used to. There are no levers or buttons to push to make the Glock fire, and that bothers some people. However, and contrary to what some would have you believe, the Glock is no more "dangerous" than any other pistol. The shooter must keep his finger off of the trigger until ready to fire, just as with any other handgun. Pulling the trigger fires the weapon. Simple.

The Glock 20 has a standard magazine capacity of fifteen cartridges, giving a total capacity of sixteen of the powerful 10mm cartridges at the shooterís disposal. The trigger pull on the sample Model 20 measured five pounds and ten ounces, and was smooth and easy to operate. The barrel length on the Glock 20 measures four and six-tenths inches (4.6"), and has Glockís hexagonal rifling. The slide is finished in their tough Tenifer coating, which has proven to be very durable over the years.

For testing the Model 20, I gathered an assortment of eighteen different types of factory ammo from three sources. I fired all loads over the screens of my PACT chronograph at a distance of ten feet from the first screen. Actual muzzle velocity will be a bit higher. Air temperature was around fifty-two degrees with a humidity of near fifty percent.  The velocities are listed in feet-per-second (fps).  Bullet weight is listed in grains. The chronograph results are listed below.

Manufacturer Bullet Velocity
Buffalo Bore 180 Gold Dot HP 1328
Buffalo Bore 200 FMJ-FN 1184
Cor-Bon 180 Bonded Core 1233
Cor-Bon 200 JFN 1071
Cor-Bon 165 JHP 1277
Cor-Bon 135 JHP  1441
Cor-Bon 140 DPX  1352
Glaser 115 Blue 1516
Glaser 115 Silver 1528
Double Tap  165 Gold Dot HP 1380
Double Tap 155 Gold Dot HP 1441
Double Tap  200 FMJ-FN  1225
Double Tap  200 XTP-HP 1216
Double Tap  230 HP 970
Double Tap  180 Gold Dot HP 1331
Double Tap  135 JHP 1509
Double Tap  165 Golden Sabre HP 1394
Double Tap  180 Golden Sabre HP 1259

All loads tested performed very well. The only problem encountered was with the Double Tap Equalizer 230 grain load. Three times during testing the slide failed to go completely into battery with that load and that load only. A gentle tap on the rear of the slide popped it into battery. Everything else fed, fired, and ejected flawlessly.  The Equalizer load might have just been a fluke with this particular pistol, and I would certainly try it in other pistols before making a judgment either way. I would recommend any of these other loads to be carried in the Model 20, choosing the one that best suited the situation. The heavier bulleted loads should be ideal for hunting heavy deer, hogs, and black bear. The lighter hollowpoints should work very well for social work. The Glasers are a specialized load from Cor-Bon that are pre-fragmented to create maximum tissue damage with limited penetration.  Accuracy was good with most loads tested; better than with other Glocks which I have used in the past. The 10mm has a good reputation for accuracy in quality pistols,  and the Model 20 is a quality pistol.  I could keep most shots into the two-inch range at twenty-five yards, with the misses being my fault. Most ammunition was, however, expended on rocks and sticks. It was a pleasure to shoot the Glock 20.

The Glock Model 20 is not for everyone, it is indeed a fine pistol for experienced shooters who want more power than is commonly available from the usual choice of auto pistol cartridges. It is relatively light at just 30.9 ounces, unloaded. It is flat enough to conceal well in a proper holster, and the edges are smooth to not get caught on clothing or skin. As is, it is a very good hunting pistol for medium game. For social carry, I would add tritium night sights to the weapon and stoke it with good hollowpoint ammo, as represented by any of the fine loads listed above, but would try any load in the individual weapon in which it will be carried to assure perfect function.  The 10mm is a cartridge deserving of greater popularity, and the Glock 20 is a fine platform from which to fire it.

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Jeff Quinn

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The Glock Model 20 is a potent package, with 16 rounds of powerful 10mm ammo.



The Model 20 comes equipped with two magazines, a magazine loading tool, cleaning rod, manual, cable lock, and plastic case.





Slide release is out-of-the-way but easy and positive for either right-handed or left-handed shooters.



The Model 20's grip is perfectly-sized for shooters with medium to large hands.







Sights are of a high-visibility fixed combat style, but Jeff would add Tritium night sights for serious carry use.





 Author tested the Model 20 with a variety of factory ammo featuring different bullet weights and styles.



The fine 10mm Auto cartridge has found a fine home in the Glock Model 20.