The Glock 20C, A 10mm Auto Pistol for the Outdoorsman

By Chuck Hawks and Nathan Rauzon

G 20
Illustration courtesy of Glock, Inc.

The G20 and G20C, chambered for the 10mm Auto cartridge, are Glock's most powerful pistols, and the models best suited for deer hunting or protection in the field. They are built on the large frame, which they share with the .45 ACP caliber G21 and G21C. They are also Glock's largest and heaviest pistols, although far lighter than a Colt 1911 Government Model 10mm or .45 ACP pistol.

The large frame Glocks have large grips, a point of criticism from those with small hands. The cartridges are large, the double stack magazine is wide, and consequently the grip is thick. That, coupled with the Glock Safe Action's inherently long 1/2" trigger movement--and hence trigger reach--means that the end pad of the trigger finger of my medium size hands contacts the trigger.

This is how a pistol trigger should be pulled, but those accustomed to using the first joint of the trigger finger may have a problem unless they have large hands. And people with small hands may have to slide their shooting hand around the grip just to reach the trigger.

On the plus side, the thick grip means a larger contact surface against the palm of the hand. This spreads the force of recoil over a larger area and makes the pistol more pleasant so shoot.

The "C" designation refers to compensating slots cut into the muzzle end of the barrel to help control muzzle jump. Otherwise the Glock 20 and 20C models are identical. We requested the ported G20C for this review, as the previous Glock pistols we have reviewed have not had this feature.

Compensated Glock
Compensated Glock firing. Illustration courtesy of Glock, Inc.

The history of Glock pistols has been covered in some detail in previous articles, perhaps most notably in the Guns and Shooting Online review of the G17, so we will not go into it in detail here. Suffice to say that Gaston Glock's polymer framed wonder pistol has had a greater impact on pistol design than any gun since John Browning's famous Model 1911. Today virtually every major autoloading pistol manufacturer except Colt offers a polymer framed pistol or two, and some are shameless copies of the Glock design. If being copied is the sincerest form of flattery, the Glock pistol may well be the most "flattered" autoloading pistol design in history. All Glock pistols, from the smallest to the largest, are based on the same Glock Safe Action, and most internal parts are interchangeable between models.

The Glock Annual 2006 catalog stresses that the success of Glock pistols is primarily due to six key factors. These are identified as simplicity, durability, reliability, accuracy, safety, and ease of maintenance. To briefly explain these six points, we will simply go down the list.

Simplicity. All Glock pistols are made with 34 or 35 parts. And, as already noted, all Glock pistols use the same Safe Action.

Durability. Glock pistols have routinely been subjected to torture tests that would disable other pistols. Many Glocks have fired over 100,000 rounds and still operate correctly.

Reliability. Glock pistols have been tested and adopted by police and military units all over the world (including NATO countries.) Almost the only way to jam ("stovepipe" in this case) a Glock is to "limp wrist" it--not hold the pistol firmly when it is fired--and this is considered a user malfunction, not a pistol malfunction per se.

Accuracy. Glock pistols come with hammer forged barrels using hexagonal rifling that is less likely to collect accuracy degrading lead, copper, and powder fouling than barrels with standard lands and grooves. Glock barrels often increase in accuracy after firing thousands of rounds.

Safety. Glock pistols incorporate three internal safeties: a trigger block safety, a firing pin safety, and a drop safety. Nothing needs to be remembered or manipulated by hand to render a Glock pistol safe before or after firing. All that is necessary is to follow the basic safety rule of keeping your finger off of the trigger until you intend to shoot the pistol.

Ease of maintenance. A Glock can be field stripped for cleaning and normal maintenance without tools, and detail stripped using only a 3/32 punch to remove three pins. (In a pinch, anything that can be used to shove out the pins will do, including a small finishing nail, paperclip, etc.)

Here are the catalog specifications for the Glock 20C pistol:

  • Action - Safe Action (constant double action mode)
  • Caliber - 10mm Auto
  • Overall length - 7.59" (slide)
  • Height - 5.47" (including magazine)
  • Width - 1.27"
  • Sight radius - 7"
  • Barrel length - 4.6"
  • Barrel rifling - Hexagonal profile, 1 in 9.84" right hand twist
  • Magazine capacity - 15
  • Weight - 27.34 ounces (without magazine)
  • Empty magazine - 2.64 ounces
  • Full magazine - ~11.46 ounces
  • Trigger pull - 5.5 pounds (standard)
  • Trigger travel - 0.5"
  • 2006 MSRP - $676

There are not many factory options for Glock 20/20C pistols, but there are some. USA Glocks are available with fixed, adjustable, and tritium night sights (all of the square notch Patridge type). The frame can be black or OD (olive) green. Reduced capacity 10 round magazines are available. There is a 6" hunting barrel option (not ported) for an additional $135 (in 2006).

The after market has devised a bewildering array of accessories to "improve" Glock pistols. Since the basic Glock is arguably the best autoloading service pistol in the world, very little improvement is necessary or desirable. We would go so far as to council that the only worthwhile after market internal part is a target trigger connector. (Glock supplies this part only in their "Long Slide" target model pistols, and refuses to sell it separately.)

The trigger pull is nominally 5.5 pounds with the standard trigger connector (actually measuring about 7.5 pounds in the case of our test pistol, as measured by our RCBS trigger pull scale), but heavier and lighter trigger connectors are available from Glock and/or the after market. An after market "target" trigger connector is the one part that we routinely add to our Glock pistols. These "3.5 pound" trigger connectors reduce the actual trigger pull to around 5 pounds (4.75 pounds in the case of our test pistol), or close to what the trigger pull was supposed to be in the first place.

While the pistol is apart to install the new connector, it is a good idea to stone (polish) the key engagement surfaces. These include the end of the trigger bar where it bears against the connector and the end of the cruciform sear where it bears against the striker tang.

Glock pistols have changed very little since they were introduced in 1982. Gaston Glock got it right the first time. One minor change is the provision of accessory rails for gun mounted flashlights, laser sights, etc. below the forward part of the frame.

The square outline of the slide and the hooked, concave front of the trigger guard remain as always. These are two features that we wish the company would change. The beveled front and top frame edges of the G34 are more attractive and easier to slip into a holster. And a normal, rounded trigger guard front strap would be a definite aesthetic improvement.

The most exciting aspect of the Glock 20C, aside from its ported barrel, is the 10mm Auto cartridge for which it is chambered. This is the most powerful cartridge available in a Glock (or most other auto pistols). Depending on the loads you compare, it is roughly similar in energy to the full power .357 Magnum or medium velocity .41 Magnum revolver cartridges. The 10mm Auto, for instance, is the only auto pistol cartridge seriously considered in the article "Handguns for Protection in the Field," which can be found on the Handgun Information Page.

The weakness of most handgun bullets is their poor sectional density (SD), which compromises penetration. The 10mm Auto cartridge is particularly deficient in this area, as it is not offered with the relatively heavy for caliber bullets available in the magnum revolver cartridges. Here are some SD figures for common 10mm (.40 caliber) bullet weights:

  • 135 grain, SD = .121
  • 150 grain, SD = .134
  • 155 grain, SD = .138
  • 180 grain, SD = .161
  • 200 grain, SD = .179

Considering that a SD of around .200-.205 is generally considered the minimum for hunting CXP2 game with a rifle, these are not impressive numbers. For comparison, the SD of a 180 grain .357 Mag. bullet is .202 and the SD of a 270 grain .44 Mag. bullet is .210.

For hunting CXP2 game (such as North American deer) with a 10mm pistol, we suggest a bullet that both expands and has a reputation for good penetration. Examples of such bullets that are widely distributed include the Barnes-X, Hornady XTP, Nosler Partition, and Speer Gold Dot.

Among factory loads, the Winchester Super-X load using a 175 grain Silvertip JHP bullet is a deer load worth considering. This load advertises a muzzle velocity (MV) of 1290 fps and 649 ft. lbs. of muzzle energy (ME).

Hornady offers a 180 grain HP/XTP bullet at a MV of 1180 fps and ME of 556 ft. lbs. Hornady also offers a 200 grain HP/XTP bullet at a MV of 1050 fps and ME of 490 ft. lbs. The advantage to this bullet on larger game is its superior sectional density (SD) compared to the lighter bullets.

Cor-Bon is famous for high performance handgun ammo. Their DPX (deep penetrating) line includes a 155 grain Barnes X-Bullet at a MV of 1200 fps with 496 ft. lbs. of ME. This is probably the best anti-personnel load that we tried in the 10mm Glock and would also be a good choice for hunting the smaller species of game, such as coyotes, chamois and roe deer.

The Cor-Bon Hunter line includes a 180 grain bonded-core soft point bullet at a MV of 1320 fps and ME of 696 ft. lbs. This latter offering is probably as good as it gets in a widely distributed 10mm factory load for hunting CXP2 class big game.

Stars and Stripes Custom ammunition also generously supplied 10mm ammunition for this review. Easy to order online or by telephone, Stars and Stripes offers a wide variety of very high quality 10mm loads among their Production offerings.

Of particular interest to the handgun hunter are the 180 grain Hornady HP/XTP bullet at a MV of 1280 fps, the Speer 180 grain Gold Dot HP at a MV of 1269 fps, and the 200 grain Hornady HP/XTP at a MV of 1170 fps. Any of these should be adequate CXP2 game loads within the range limitations of the 10mm cartridge, and the S&S load using the 200 grain Hornady XTP bullet would be my choice for protection against large predators in the field.

Of course, Stars and Stripes will custom load any available bullet to your specification. They state on their web page that, "Anything within the limits of safety can be made."

The ballistics of all of these 10mm Auto loads using 175-180 grain bullets are similar, so we will use the Winchester figures for their 175 grain Silvertip as representative of full power loads. Here are the down range velocity and energy figures: 1141 fps / 506 ft. lbs. at 50 yards, 1037 fps / 418 ft. lbs. at 100 yards.

The midrange trajectory of a full velocity 175-180 grain 10mm bullet over 100 yards is around 3", so a G20 can reasonably be zeroed at 100 yards for deer hunting without undue concern about shooting over at intermediate distances. That will extend the MPBR to about 125 yards, which is well beyond the 10mm bullet's effective range in terms of remaining energy for hunting CXP2 class game, but is still quite useful for harvesting smaller animals such as coyotes.

We'd recommend limiting shots to about 50 yards on CXP2 class game with any 10mm pistol due to the limited energy available. We recommend the same range limitation for full power .357 Magnum revolver loads, which deliver a similar amount of energy down range. (For example, the Winchester Supreme 180 grain .357 load carries 416 ft. lbs. of energy at 100 yards.)

Of course, while power and trajectory are legitimate concerns, of equal importance is accuracy. Any 10mm big game hunting pistol needs to be capable of shooting 2" groups at 25 yards or 4" groups at 50 yards. Expressed differently, the pistol and shooter together need to be able to deliver groups no larger than 8 MOA center to center, from field positions, at the maximum range at which they will attempt a shot.

We did our shooting at the Isaac Walton gun range south of Eugene, Oregon. At this outdoor facility they offer 25, 50, 100, and 200 yard ranges with covered firing positions. The latter are particularly important, since Spring is part of the rainy season in Western Oregon. (Actually, three out of the four seasons are rainy seasons in Western Oregon.) Anyway, it rained during our visits to the range with the Glock 20C.

For test ammo we used Cor-Bon 155 grain DXP, Winchester Super-X 175grain Silvertip, and Stars and Stripes 180 grain Speer Gold Dot and 200 grain Hornady HP-XTP factory loads. Where we live 10mm Auto ammo is not readily available locally, and it is quite expensive to special order, so all of the ammunition used in the course of this review was generously contributed by those companies. Thanks, guys!

For record from the bench rest we fired 5-shot, 25 yard groups at Hoppe's Competition 25 yard Pistol Target centers using a Steady Point pistol rest. (A review of the Steady Point rest can be found on the Handgun Information Page.)

The Glock 20C immediately exceeded our 2" accuracy standard by shooting a 1 15/16" group from the shooting bench at 25 yards with the first ammunition we tried, the Cor-Bon 155 grain DPX load. We usually shoot for record at 25 yards with handguns due to the limitations imposed by our middle aged eyes peering over open sights, not due to any inherent limitation of the pistols we review.

Here are the shooting results:

  • COR-BON DPX Hunter (155 grain) - smallest group 1 1/8"; largest group 4 1/8"; mean average group = 2.37".
  • Stars & Stripes HP-XTP (200 grain) - smallest group 2 1/16"; largest group 2 3/4"; mean average group = 2.41".
  • Stars & Stripes Gold Dot (180 grain) - smallest group 1 15/16"; largest group 3"; mean average group = 2.58".
  • Winchester Super-X (175 grain) - smallest group 1 7/8"; largest group 4 3/8"; mean average group = 3.04".

The G20C delivered good accuracy for an autoloading pistol. It shot groups as good or better than we are usually an able to wring from our 9x19 Glocks despite the 10's greater recoil.

While we are on the subject of recoil, the G20C is not a particularly difficult pistol to control. Glocks are generally known as light kicking guns because of their natural grip angle, thick backstraps, the slight "give" built into their polymer frames, their low line of recoil, and their exceptionally well balanced slides. We also think that the G20C's compensated barrel probably had something to do with the pistol's good manners.

Whatever the reason, we found the big Glock to be a rather comfortable pistol to shoot, considerably more so than either the Colt Python .357 Magnum or Ruger Super Blackhawk .44 Magnum revolvers shooting full power 180 and 240 grain factory loads (respectively) that we brought along for comparison.

Nor did the G20C seem nearly as loud as the magnum revolvers, despite its compensated barrel. The blow-by from the revolvers' cylinder to barrel gap made them much noisier than the G20C. On balance, we were quite pleased by our decision to review the compensated version of the 10mm Glock. We feel that the ported barrel is a good idea for a cartridge as powerful as the 10mm Auto.

Another advantage in the Glock's favor is its relatively light weight, which makes it a pleasure to carry afield. A Ruger Blackhawk .357 Magnum revolver with a 4 5/8" barrel, for instance, weighs 40 ounces empty, or about 33% more than a G20 with an empty magazine. Fully loaded, the Glock will shoot 15 times without reloading, compared to the revolver's 6 shots. (Realistically, though, if a hunter can't do it with 6 shots he almost certainly can't do it at all.)

Unlike other autoloading hunting pistols, the Glock has no manual safety to fumble or hammer to cock. It is fast and silent to get in action. A single smooth pull on the trigger moves the gun from completely safe to "bang!"

A rather specialized role for which the Glock 20 is ideally suited would be when one pistol had to be chosen for open carry in the field as protection against large predators and for concealed carry in a populated environment as protection against two-legged predators. We are thinking of a number of Third World countries where a visitor, regardless of his or her credentials, would likely find it nearly impossible to get more than one pistol past Customs. The G20's power and flat trajectory, coupled with its relative compactness and light weight, make it ideal for such situations.

Like every other Glock pistol that we have reviewed, the big Glock was 100% reliable. There were no malfunctions of any kind.

The bottom line is that the Glock 20C is a very good choice for the person who prefers an autoloader in the field. Nathan particularly appreciated the big Glock's virtues. For him it's the perfect field pistol. His check will be going off to Glock in lieu of returning the G20C.

Back to the Product Review Page

Copyright 2006 by Chuck Hawks. All rights reserved.