By John Rogers

**** GUN REVIEW OVERVIEW ****

1.DESCRIPTION OF GLOCK 20 TESTED

2. 25, 50, 82 & 100 YARD FIRING TESTS

3.SEMI-AUTO PISTOL VULNERABILITIES

4.GLOCK "ASSETS"

5.HIGHLIGHTS OF CARING FOR A GLOCK PISTOL

6.GLOCK MEASUREMENTS BEFORE AND AFTER FIRING 110 RDS.

7. DIRECTORY OF ON-LINE PHOTOGRAPHS. (All pictures associated with this Glock 20 Gun Review can be viewed at GLOCK 20 REVIEW PICTURES  )

******************************* DESCRIPTION OF THE NEW GLOCK 20 (10mm) TESTED *************************

A new Glock 20 (10mm) semi-auto pistol using the stock 4.6-inch long barrel, a 6-inch long Glock hunting barrel, and fixed, three dot, tritium night sights was tested for accuracy at 25, 50 and 82 yards. The 6-inch long Glock hunting barrel can be purchased directly from Glock for around $135.00; it easily installs and removes just like the standard 4.6-inch long barrel. The standard 4.6-inch long 10mm barrel sticks out of the slide barrel hole about 1/8 inch, and the 6-inch long Glock hunting barrel sticks out just over 1.5 inches.

Glock's "two post and a ball" gun sight is an extremely fast defensive sight. It is easy to see during almost any daylight condition. Glock's fixed, three dot, tritium night sights (made by Meprolite or Trijicon) would be better suited for low-light hunting conditions, as a bright target is a bit difficult to sight on.

Rear fixed Glock sights are available in four heights: 6.1mm, 6.5mm (standard), 6.9mm, and 7.1mm. I purchased a Glock three-dot night sights in the standard 6.5mm height, directly from Glock, along with Glock's rear sight adjustment tool. Changing and then adjusting the rear sight for windage using Glock's rear sight change/adjust tool was easy and very precise, much more precise than what a 3-dot sight system's shoot accurately could attain (pictures 2 - 5).

******************************* 25, 50, 82, & 100 YARD FIRING TESTS ******************************

1. CONDITIONS: Barometric Pressure: 30.2 Inch Hg.; Temp.: 38-55 F, Relative Humidity: 40%, Cross winds: 0-2 MPH

2. AMMO USED: (PICTURE ‘1’)

**SELF-DEFENSE**

FEDERAL 10mm 180 gr. JHP HI-SHOK 1030 fps / 425ft/lbs.

WINCHESTER 10mm 175gr. SILVER TIP STHP (X10MMSTHP)

**HUNTING**

COR-BON 10mm 180gr. BONDED CORE SP 1300fps / 676ft/lbs

COR-BON 10mm 200gr. FP PENETRATOR 1150fps / 587ft/lbs

3. SIGHTING: While sighting on the target, I placed the target on the top center point of the center dot.

Twenty-four targets consisting of 5-shot groups were shot from 25, 50, 82 and 100 yards. Pictures of the targets can be viewed on-line at GLOCK 20 REVIEW PICTURES . The target pictures are numbered from T1 to T24. Each target has a low and high resolution picture. For example, target 1 has two pictures with the name T1L (low resolution) and T1H (high resolution). The description of each picture is given on the last page of this review.

** 25 YARD TARGETS 1 thru 10 (T1 thru T10) **

Targets 1 thru 10 (T1 - T10) are shot from 25 yards while using only a flimsy hand support (there was no arm or body support). The sun was about 40 degrees to the horizon and at a 2 o’clock position. Targets 1 thru 3 (T1-T3) and 7 thru 10 (T7-T10) were shot using the Glock 6-inch long hunting barrel, Targets 4 thru 6 (T4-T6) using the 4.6-inch long barrel. Federal 180 gr. JHP ammo was used on targets 1, 4, 9 (T1, T4, T9); Cor-bon 200gr. Penetrator on targets 3, 6, 7 (T3, T6, T7); Cor-bon 180gr. Bonded Core SP on targets 2, 5, 8 (T2, T5, T8).

Before shooting target 3 (T3), the rear sight was adjusted 1/2 turn to the left using the Glock Sight Adjust/Removal tool (pictures 2 thru 5; picture 6 is for clarification). A final rear sight windage adjustment of 1/4 turn to the right was made before shooting target 9 (T9). The 6-inch long hunting barrel was cleaned before shooting target 7 (T7). No other adjustments or cleaning were made during the shooting test.

Out of the 120 rounds shot during the accuracy test, a single jam (picture 7) occurred while feeding the fourth round of Target 5 (T5); the magazine had to be removed to clear this jam. The few jams I’ve experienced with Glock pistols are almost always case ejection jams that occur while shooting reloaded ammo. Since this was the only jam to occur with the 120 rounds fired, and because it was a feed jam, I suspect that the magazine wasn’t fully engaged.

The best 25 yard 4-shot group was 1-29/32 inches, which was made while shooting Federal 180gr. JHP thru the 6-inch long hunting barrel (target T1). The best 25 yard 5-shot group was 2-26/32 inches, which was made while shooting Federal 180 gr. JHP thru the 4.6-inch long barrel (target T4).

** 50 YARD TARGETS 11 thru 16 (T1 - T10) **

50 yard targets 11 thru 16 (T11 - T16) were shot from a Protektor rabbit-ear rear shooting bag placed on a car roof. The sun was almost directly overhead. Targets 11 thru 14 (T11-T14) were shot using the Glock 6-inch long hunting barrel, Targets 15 and 16 (T15-T16) using the 4.6-inch long barrel. The Federal 180gr. JHP ammo was used on target 13 (T13), Cor-bon 200gr. Penetrator on targets 12 and 16 (T12, T16,), Cor-bon 180gr. Bonded Core SP on targets 11 and 15 (T11, T15), and Winchester 175gr. Sliver Tip Hollow Point (STHP) on target 14 (T14).

On the 11th target (T11), the 1-inch diameter, red stick-on bullseye was the point of aim. Likewise, on targets 12 thru 16 (T12 - T16), the 3-inch diameter, red, stick-on bullseye was the point of aim. The 6-inch long hunting barrel was used with targets 11 thru 14, and the 4.6-inch long barrel with targets 15 and 16.

The best 50 yard 4-shot group was 2-18/32 inches, which was made while shooting Cor-bon 200 gr. Penetrators through the 4.6-inch long barrel (target T16). The best 50 yard 5-shot group was 4-14/32 inches, which was made while shooting Cor-bon 180 gr. Bonded Core SP thru the 6-inch long hunting barrel (target T11). With the exception of target #15 (T15), at 50 yards the hollow point ammo is probably starting to be outperformed by the non-hollow point ammo. Although the gun’s sights weren’t accurate enough to precisely determine bullet drop, my guess is that at 50 yards the bullet drop was somewhere between 1-2 inches.

** 82 YARD TARGETS 17 thru 22 (T17 - T22) **

82 yard targets 17 thru 22 (T17 - T22) were shot from a Protektor rabbit-ear rear shooting bag placed on an 8-inch wide board that was the shooting platform of the deer blind I was shooting from. The deer blind was completely shaded, but the target was completely covered in bright sunlight. Being in the shade while shooting at a brightly lighted target was difficult, as the three dots of the three dot, tritium night sights were very difficult to see (back light was badly needed).

Targets 17 thru 22 (T17 - T22) were shot using the Glock 6-inch long hunting barrel. Cor-bon 200 gr. Penetrators were used on targets 17, 19 and 21 (T17, T19, T21); Cor-bon 180gr. Bonded Core SP were used on targets 18, 20 and 22 (T18, T20, T22). The stick-on red bullseye was the point of aim.

The best 82 yard 4-shot group was 9 inches while shooting Cor-bon 200gr. Penetrator (target T19). The best 82 yard 5-shot group was 13-1/4" while shooting Cor-bon 180 gr. Bonded Core SP thru the 6-inch long hunting barrel (target T22). The three dot, tritium night sights weren’t accurate enough to allow for accurate estimation of bullet drop, but my guess is that at 82 yards the bullet drop was somewhere between 3 to 5 inches while using the 6-inch long hunting barrel.

** 100 YARD TARGETS 23 AND 24 (T23 and T24)**

100 yard targets 23 and 24 (T23 and- T24) were shot from front and rear sandbags placed on a Protektor rifle rest w/ pistol rest attachment. The shooting location was around 8-10 feet elevated to the target. The 6-inch long hunting barrel was used.

Target 23 was shot using Winchester 175 gr. STHP, and target 24 with Cor-bon 180 BCSP ammo. Only three out of five bullets hit each target, but I’m sure the four strays barely missed. The stick-on red bullseye just above each target was the point of aim. The 3-shot group on target 23 (T23) was 8.5 inches; and the 3-shot group on target 24 (T24) was 7.5 inches.

** BULLET SPEED **

All 120 bullets shot during this test were measured for speed in feet per second by an Oehler 35 Proof chronograph with printer (picture 8 and 9) at about five feet from the muzzle. The 35P chronograph uses three detectors, instead of two, to measure the bullet speed twice.

On each of the targets is the printout from the 35P chronograph printer. On the first five lines of each printout is the bullet’s Proof Velocity, followed by the Shot Number, and Primary velocity. On target 1 (T1) the first line shows a Proof Velocity of 1,089 ft./sec., the bullet number 01, and a Primary Velocity of 1,067 ft./sec. (1089 - 01 - 1067). On each of the Oehler printouts below the five bullet number and speed lines are five more lines (‘------’ lines not included). These five lines give the group’s Highest Velocity, Lowest Velocity, Extreme Velocity Spread, Mean or Average Velocity, and Standard Deviation. For target 1 (T1), the Highest Velocity is 1,070 fps, the Lowest Velocity is 1,052 fps, the Extreme Velocity Spread is 18 fps, the Mean or Average Velocity is 1,060 fps, and the Standard Deviation is 7 fps. (note that on target 2 (T2), the bullet speed is the only correct information).

A +p+ 160 gr. 1,800 fps 10mm handload is something I'll definitely pursue with this gun.  Actually, a personal defense load of Winchesters SXT ammo loaded to +p+ is a handload  that no freedom-loving citizen should be without.  The SXT bullet has probably the most R&D of any pistol bullet ever -- and it is one of the best defensive loads to use for personal protection against assailants that aren't wearing body armor.  In the beginning, Winchester's  SXT bullet was called Black Talon because of the sharp pointed star is mushrooms into, and because of the black lubalux coating it was originally coated with ---- under "pinocchio cocaine anus-eater" Clinton's reign of terror, pinocchio had the controlled mainstream media give huge amounts of coverage of a few unfortunate  high-profile shootings . . . under pressure from slave-master media moguls directed by "pinocchio cocaine anus-eater" Clinton, Winchester temporarily pulled the ammo . . . sometime later Winchester re-released the Black Talon without the black lubalux coating calling it SXT personal defense ammo.  I HIGHLY RECOMMEND PURCHASING ALL THE +P AND +P+ SXT AMMO WHILE IT'S STILL AVAILABLE TO THE GENERAL PUBLIC  ---- it's just a matter of time before the owners of the privately-owned non-federal Federal Reserve install another treasonous, traitorous public servant leader.  Until our U.S. monetary system is owned by the government like it was before 1913 -- the less than a dozen inbreed families that own the Federal Reserve will continue in their pursuit of world-wide enslavement. 

** BULLET SPEED GAINED WHILE USING THE 6-INCH LONG GLOCK HUNTING BARREL **

The speed of the Cor-bon 200 gr. Penetrator was around 1,191 fps while using the 4.6-inch barrel. While using the 6-inch long barrel, a 41 fps increase brought the bullet speed to around 1,136 fps, which is a speed increase of about 3.8%.

The speed of the Cor-bon 180 gr. Bonded Core SP was around 1,191 fps while using the 4.6-inch barrel. While using the 6-inch long barrel, a 70 fps increase brought the bullet speed to around 1261 fps, which is a speed increase of around 5.6%.

The speed of the Federal 180 gr. JHP was around 1,011 fps while using the 4.6-inch barrel. While using the 6-inch long barrel, a 49 fps increase brought the bullet speed to around 1060 fps, which is a speed increase of around 4.6%.

The Winchester 175 gr. STHP wasn’t shot through the 4.6-inch long barrel.

** SHOOTING OBSERVATIONS **

As previously mentioned, the three-dot tritium night sights need back lighting when shooting at a brightly lighted target from a shaded position during daytime.

If a more accurate hunting sight were used, such as the triangular/trapezoid sights used on Steyr M-series handguns----the 5-shot group diameters disclosed in this review could easily be reduced in half. If using a "fine" hunting sight and 6-inch long Glock hunting barrel, I feel that the Glock 20 could be used to shoot medium size game out past 100 yards, possibly 150 yards. After shooting the new Glock 20 for this test, I went over to a favorite hunting spot and killed a small buck at about 40 yards that afternoon.

NOTE: If you know of an accurate hunting sight that can be installed on Glock pistols without having to modify the Glock---- PLEASE LET ME KNOW ABOUT IT. E-mail: SHOOTER@MILITARYOPTICS.COM

*************************** POSSIBLE SEMI-AUTO PISTOL VULNERABILITIES *********************

** USE ONLY NEW, HIGH QUALITY, BRASS CASE AMMUNITION **

All semi-auto pistols are temperamental when (1) not cleaned/maintained properly, and (2) not fed new, high quality, brass case ammo. My experience with Glock pistols has been that they feed, fire and eject reliably all new, high quality, brass case ammo as long as the Glock is being at least minimally maintained----and as long as solvent or gun oil is never allowed to enter the firing pin channel! (Note: heavier recoil springs must be used with +P+ ammo to prevent excessive gun wear).  The few jams I've experienced with Glock pistols were ejection jams ("stove pipe" jams in which the case gets caught sideways in the breech), which were almost always caused by using reloaded ammo instead of new, high quality, brass case ammo.  As previously mentioned, the single feed jam (picture 7) that occurred during this review was probably caused by the magazine not being fully engaged (although adequate, Glock magazines' magazine catch as never impressed me)..

EXTRA: Most ejection jams can easily be cleared while in the aiming position by simply (1) inverting the gun, (2) pulling the slide back and letting the jammed case fall out, and (3) releasing the slide.

** ONLY ONE BREAKAGE PROBLEM **

Out of all the Glock pistols I've owned, I've experienced only a single breakage problem. At around the 1,160 round fired through a Glock 19, the plastic end (barrel lug end) of the recoil spring assembly broke, allowing a portion of the recoil spring to come off its plastic centering rod. This recoil spring assembly breakage is very rare; however, because of this single breakage experienced, I do recommend Glock pistol owners purchase and keep handy a spare recoil spring assembly, just in case. 

I’ve heard that the Glock will still shoot with the type of aforementioned broken recoil spring assembly.  Glock will probably replace this plastic part with lightweight allow metal at some point, if they haven't done so already.

** UNINTENTIONAL MAGAZINE RELEASE IS POSSIBLE WITH ALL SEMI-AUTO PISTOLS **

The first thing that should be done upon handling any semi-auto pistol is tap the bottom of the magazine to make sure it is engaged.  Developing this as a habit is very important to your safety.

The only accidental magazine release that I've experienced with Glock pistols was a single incident in which I was carrying a Glock 19 in an under-the-shoulder holster while doing rigorous shoooting. I got the urge to see how fast I could bring the pistol to the firing position, and upon quickly bringing the pistol to the aiming position, the magazine fell to the ground.  The Glock magazine catch has never impressed me.

** POSSIBLE CORROSION PROBLEM **

While wearing a Glock in an under-the-shoulder or waistband holster during warm weather, sweat has sometimes seeped into the slide and barrel area just in front of the barrel hood. Sweat will remain in this area undiscovered until the gun is disassembled for cleaning, and if the gun isn't cleaned for months, the salty sweat will start slowly corroding the metal.

During hot weather, to prevent sweat from causing corrosion in the area just in front of the barrel hood, at the end of the day or night I remove the slide, remove the barrel from the slide, and then wipe the slide and barrel area of any accumulated sweat. Then I lightly coat the affected barrel and slide area with gun oil.

** FRONT SIGHT CAME OFF AFTER THE GLOCK PISTOL FELL ONTO A CONCRETE FLOOR MORE THAN A DOZEN TIMES **

I once used a waistband holster for carrying a Glock 27 pistol during warm weather. This waistband holster was a bit narrower and thinner than most, which made it more comfortable to wear during warm summer weather. Because this waistband had no Velcro or snap straps to securely hold the gun in place, whenever bending over, my Glock 27 pistol would fall to the floor----many times it fell on a concrete floor while doing car maintenance/repair work. After a dozen or more falls, the front sight came loose and disappeared (front sight is simple to replace). Surprisingly, there is no evidence on this Glock 27 pistol that it has fallen on a concrete floor--the Tenifer metal treatment process used on the barrel and slide of Glock pistols makes the metal surface extremely hard and scratch resistant.

EXTRA: The standard front plastic sight has a hollow post that extends down underneath the sight and into a hole in the slide. After the post is placed into the slide hole, a tapered plastic pin is pressed into the hollow post to expand it and hold the front sight in place. To gain maximum hold, the tapered plastic pin should only be pressed in flush with the bottom of the hollow post, because pushing the tapered pin in further will only weaken the hold. In contrast, night sites are made of metal in which an internally threaded hollow metal post of the front sight is held in place by a tiny bolt. Not over or under-tightening the tiny bolt is difficult (I used Loctite 272 thread locker on the threads, and it hasn’t loosened as of yet).

** POLYMER GLOCK PISTOL FRAMES **

A 1999 Glock advertisement brochure states that Glock handgun frames are made out of a synthetic that is stronger than steel, yet 86% lighter.  It also states that Glock handguns can withstand a temperature range from -40F to 392F. Lexan ® polycarbonate can continuously withstand 180F temperature. A 1994 brochure states that the synthetic material cannot break down, but this statement isn’t included in the 1999 advertisement. Glock plastic frames are definitely made of an ultra high quality patented plastic (I'd like to know more); however, in my opinion, the less exposure to sunlight any type of plastic receives, the longer it will last.

**************************************** GLOCK "ASSETS" ********************************************

Many years ago, I bought my first Glock pistol for its (1) high-capacity, (2) corrosion resistance, (3) reliability, and (4) fewer parts.  Other qualities/characteristics that I've come to appreciate over the years are (1) consistent trigger pull, (2) polygonal barrel rifling, (3) NATO +P+ ammo capability with proper recoil spring installed , (4) trigger location shows if the gun is cocked or not cocked, (5) no conventional safety, and (6) the extremely safe Glock striker fire system.  Also, I like the trigger pull characteristics during fast multiple shots. 

** EXTREMELY CORROSION RESISTANT **

** TRIGGER PULL IS CONSISTENT **

Because of the design of the striker fire trigger system, the trigger pull is the same on every shot.

Standard trigger pull is 5.25 lb.. The trigger pull on the new Glock 20, shot for this review, measured from 5 to 6 pounds during multiple test pulls. If a lesser trigger pull is desired, Glock offers the 3.5 lb. "New York Trigger Spring" or 2 lb. "New York Trigger Spring Plus" (appropriate names, indeed).

** POLYGONAL RIFLING ADVANTAGES/BENEFITS **

Glock barrels have either of two types of polygonal rifling: .45 cal barrels use octagonal rifling, all other Glock barrels use hexagonal rifling. While looking at the inside of a Glock barrel you'll see the swirl created by the polygonal rifling, but you'll see that the lands and grooves are smooth, and that they blend together making them somewhat difficult to distinguish between.  Glock barrels’ polygonal rifling and minimal bore dimensional variance gives the bullet a better seal with less gas pressure loss, thus allow for higher bullet velocity, better accuracy, and increased bullet consistency. Also, the smoothness of polygonal rifling helps to eliminate barrel fouling and makes cleaning the barrel extremely easy. Polygonal barrel rifling is commonly found on the most expensive sniper rifles (HK PSG-1 comes to mind); however, I've also seen other pistol manufacturers offer it.  Tenifer metal treatment and polygonal rifling make Glock barrels absolutely awesome.

The only disadvantage of polygonal rifling is that only jacketed bullets can be used.  Using non-jacketed lead bullets will quickly foul the bore with lead deposits, which will reduce accuracy and eventually cause dangerous pressure levels.

** +P+ AMMO CAPABILITY **

When inquiring about upper pressure limits for Glock 9mm pistols in 1994, Glock sent me their AMMUNITION SPECIFICATIONS FOR GLOCK PISTOL data sheet. It states, "GLOCK pistols are designed to be fired with NATO specification ammunition. [ ] GLOCK pistols will function properly with the new generation of 9x19mm ammunition including all +P+ and 147 grain sub-sonic ammunition currently being introduced in the United States." The Glock data sheet also states that the minimum lower limit for ammunition to be used in Glock 9mm pistols is 115 grains at 902 fps, and that the maximum pressure limit for 9x19mm ammunition should not exceed 43,500 psi.  Also catching my eye, the data sheet's Ammunition Performance Data Table details a Norma 170 grain JHP 10mm bullet shot from a 5-inch Glock barrel delivering almost 1,000 Joules of energy----WOW!  Installing the proper recoil spring for +P+ loads is necessary to allow for reliability and minimal gun wear.

**TRIGGER POSITION EASILY IDENTIFIES WHETHER THE GLOCK IS COCKED**

It's easy to determine whether a Glock pistol is cocked by simply looking at the trigger position. A forward, actually mid-position, trigger shows that the gun is cocked. A trigger that is all the way rearward shows that the gun is not cocked.

** NO CONVENTIONAL SAFETY **

Three non-conventional safeties automatically release as the trigger is pulled through. There is nothing to turn on or off, simply fire the gun at will.

** STRIKER FIRE SYSTEM IS EXTREMELY SAFE **

With the Glock cocked, the firing pin is under minimal spring tension. The striker fire trigger system further tensions the firing pin against the firing pin spring as the trigger is pulled rearward. Basically, a cocked Glock cannot fire unless the trigger is pulled rearward to further tension the firing pin against the firing pin spring. The trigger cannot move rearward unless the trigger lever safety is first depressed, which is naturally depressed upon pulling the trigger. Unlike with some handguns, Glock pistols cannot accidentally fire without pulling the trigger (all the way through).

************** IMPORTANT HIGHLIGHTS OF CLEANING A GLOCK **************

**FIELD STRIPPING A GLOCK PISTOL**

1. REMOVE THE MAGAZINE.

2. CYCLE THE SLIDE TO CLEAR THE CHAMBER.

3. WITH GUN POINTING IN A SAFE DIRECTION, PULL THE TRIGGER.

4. PULL THE SLIDE BACK .12-INCH, THEN PULL DOWN THE SLIDE LOCK, AND THEN PUSH THE SLIDE FORWARD

TO SEPARATE IT FROM THE RECEIVER.

5. REMOVE THE RECOIL SPRING.

6. REMOVE THE BARREL OUT OF THE SLIDE.

**********************************GLOCK CLEANING*********************************

Surprisingly, cleaning instructions have never been included with any of the Glock pistols I've purchased. After contacting Glock and inquiring about how to clean Glock pistols, I was sent a sheet of paper containing two sets of instructions titled (1) Cleaning The Field Stripped Pistol, and (2) Lubricating The Field Stripped Pistol.

**CLEANING THE FIELD STRIPPED PISTOL**

BARREL. After field stripping the Glock pistol, the barrel and chamber can be cleaned from the chamber end using

solvent and a bore brush. After cleaning the barrel, it should be wiped completely dry inside and out using clean

patches.

SLIDE. The slide rails can be cleaned using a patch placed on the end of a toothbrush-type cleaning tool (I use Q-tips

and pipe cleaners). If possible, the copper colored lubricant found on certain areas of the slide should not be removed,

as it helps provide long-term lubrication. The breech face and area underneath the extractor claw can be cleaned with

toothbrush-type cleaning tool and then wiped completely dry.

FRAME. Exposed parts of the frame can be wiped clean using a soft cloth or patch moistened with solvent, and wiped

completely dry (soap and water also works).

MAGAZINE. A disassembled magazine can be brushed out with a clean dry brush. The spring and follower can be

wiped with a clean, soft, dry cloth. If any lubricant or solvent is used, it must be thoroughly wiped clean to prevent

contamination and misfire of ammo (oil + solvent ruins ammo primers).

** LUBRICATING THE FIELD-STRIPPED PISTOL **

Use a clean patch slightly moistened with quality gun oil and wipe the outside of the barrel, and the barrel hood and

lugs. Wipe the front slide hole where the barrel slides through, and wipe the top inside of the slide forward of the

ejection port where the barrel hood rubs against. One drop of oil should be spread along each slide rail cut. One

drop of oil should be placed where the rear end of the trigger bar touches the connector at the right rear corner of

the frame.

WARNING: Do not allow oil to enter the firing pin channel or magazine. The magazine and breech face should be

wiped dry before reassembling. Oil or solvent left in these areas could cause contamination of the primers and failure

to fire. (GLOCK CLEANING INSTRUCTIONS, 1993)

WHAT CAN I ADD TO THE PRECEDING CLEANING INSTRUCTIONS?

**KEEP SOLVENT & OIL OUT OF THE FIRING PIN CHANNEL

Another important reason not to allow oil or solvent to enter the firing pin channel is that during firing, solvent or oil will mix with unburned powder residue and form deposits in the firing pin channel that will eventually cause a weak firing pin strike of the primer.

**POLYGONAL RIFLING GENERALLY DOESN’T REQUIRE RIGOROUS CLEANING WITH A METAL BRUSH**

Because of the smoothness of polygonal rifling, the bore remains much cleaner and is much easier to clean, as compared to conventional land and groove rifling. I’m sure this is why Glock provides a fiber brush with each new pistol, instead of a metal bore brush. After shooting the 6-inch long Glock hunting barrel for this review, I found almost no copper fouling of the bore----and the Glock bristle bore brush provided with the gun did an excellent job in cleaning the bore.

**REAPPLY THE COPPER-COLORED ANTI-SEIZE LUBRICANT AFTER EACH CLEANING**

Slide rails collect powder and other debris that need to be removed while cleaning the gun. I can't thoroughly clean a Glock pistol without removing the copper colored lubricant that was applied on the slide rails at the factory. Therefore, I reapply it after each cleaning.

The copper-colored lubricant applied at the factory is Loctite #C5-A Copper-Based Anti-Seize Lubricant. The description on my 8 oz. bottle says "C5-A Copper Based Anti-Seize Lubricant is an exclusively formulated colloidal copper compound that in effect 'copper plates' mating surfaces. It prevents seizing and galling caused by heavy loads, vibration, corrosion and temperatures up to 1800 F (980 C). For use with most metals under most conditions, including cast iron, steel, stainless steel, nickel, copper, brass, bronze, titanium, aluminum and monel." The bar code on the 8 oz. bottle I own is 0-79340-51147-7. It meets MIL-A-907; 51147; FP51147L-1.

Measurements of a new Glock 20 are given first. The measurement taken after shooting a 116 rds. are given in brackets [ ]. When using only the Starrett vernier 0-1 inch micrometer, I couldn’t discern .0001 of wear. When using the Starrett micrometer and telescoping hole gauges, a few of the barrel inside diameter measurements gave an indication of possible .0001" wear; whether there was actually any barrel wear will become clear after more firing and wear measurement tests. Caliper measurements are only accurate to .001 inch; therefore, there will have to be much wear before the caliper measurements will register any wear. There were a few barrel measurements taken where no wear should occur; however, barrels can expand, thus I chose to take the measurement.

1/16" FROM END (vertical): .6293, .6293 [.6292]

1/16" FROM END (horizontal): .6293, .6292 [.6292]

1-3/4" FROM END (vertical): .6292, .6292 [.6291]

1-3/4" FROM END (vertical): .6289, .6289, .6289 [.6289]

JUST IN FRONT OF CHAMBER AREA (vertical): .6293, .6292 [.6292]

JUST IN FRONT OF CHAMBER AREA (horizontal): .6289, .6288 [.6288]

1/16" FROM END (vertical): .6294, .6294, .6293, .6293 [.6293]

1/16" FROM END (horizontal): .6293, .6293, .6293 [.6293]

2" FROM BARREL END (vertical): .6297, .6296, .6295, .6295, .6295 [.6294]

2" FROM BARREL END (horizontal): .6294, .6294, .6294 [.6293]

3" FROM BARREL END (vertical): .6295, .6295 [.6295]

3" FROM BARREL END (horizontal): .6293, .6292, .6291, .6291 [.6292]

JUST IN FRONT OF CHAMBER (vertical): .6293, .6293, .6293 [.6292]

JUST IN FRONT OF CHAMBER (horizontal): .6290, .6290, .6290, .6290 [.6289]

DEAD CENTER OF CHAMBER (Horizontal): .6380, .6381 [.6379]

OVER GLOCK EMBLEM (Horizontal): .6385 [.6385]

LIP IN FRONT OF BARREL HOOD TO UNDERNEATH CHAMBER (Vertical): .6485, .6485 [.6484]

FORWARD LUG TO TOP OF CHAMBER (Vertical): .9857 [.9857]

REAR LUG TO TOP OF CHAMBER (Vertical): .8384, .8383 [.8383]

FORWARD LUG WIDTH (Horizontal): .3760 [.3759]

REAR LUG WIDTH (Horizontal): .3765 [.3766]

FRONT OF BARREL HOOD TO REAR OF BARREL HOOD: (CALIPER: 1.336, 1.3351, 1.3351, 1.3351, 1.3351, 1.3354, 1.3353, 1.3352, 1.3352, 1.3358, 1.3352 [CALIPER: 1.336 [MICROMETER:1.3338]] [UPDATE 59RD. THUR 4.6" BARREL: 1.3341, 1.3340, 1.3339, 1.3339, 1.3341, 1.3342]

REAR HOOD EXTENSION WIDTH: [.4272] [[59RD. UPDATE.: .4274, .4275]]

DEAD CENTER (Horizontal): .6384, .6384 [.6382]

OVER GLOCK EMBLEM (Horizontal): .6387, .6389, .6389 [.6388]

LIP FORWARD OF BARREL HOOD TO UNDERNEATH CHAMBER (Vertical): .6473, .6472 [.6472]

FORWARD LUG TO TOP OF CHAMBER (Vertical): .9873, .9873, .9874 [.9873]

REAR LUG TO TOP OF CHAMBER (Vertical): .8388, .8388 [.8389]

FORWARD LUG WIDTH (Horizontal): .3757, .3757 [.3758]

REAR LUG WIDTH (Horizontal): .3761, .3763 [.3763]

FRONT OF BARREL HOOD TO REAR OF BARREL HOOD: (CALIPER 1.335 to 1.336 [CALIPER: 1.335, 1.335 MICOMETER: 1.3354] [UPDATE 100RD. THUR 6" BARREL: 1.3341, 1.3350, 1.3345, 1.3343, 1.3341, 1.3342, 1.3341, 1.3343, 1.3350 ]

BARREL HOOD REAR EXTENSION’S WIDTH: [.4273] [[100 RD. UPDATE: .4270, .4271]]

.

**** 4.6" BARREL INSIDE DIAMETER **** (measured with telescoping gage and 0-1" micrometer)

BARREL END (just inside barrel end)

BARREL GROVES (Vertical): .4005, .4008, .4005, .4006, .4005, .4006, .4006, .4006 [.4002, .4002, .4003, .4002]

BARREL GROVES (Horizontal): .4005, .4004, .4005, .4005, .4004, .4004, .4006, .4006 [.4006, .4004, ..4004, .4006]

BARREL LANDS (Vertical): .3901, .3928, .3903, .3907, .3936, .3899, .3908, .3902, .3907, .3913, .3899, .3893, .3903, .3900, .3893, .3899, .3908 [.3904, .3900, .3901, .3903].

BARREL LANDS (Horizontal): .3901, .3903, .3902, .3900, .3901, .3912, .3901, .3904, .3906, .3903, .3902, .3902, .3901, .3903, .3904, .3901 [.3904, .3904, .3898, .3900, .3901]

**** 4.6" BARREL CHAMBER INSIDE DIAMETER **** (measured with telescoping gage and 0-1" micrometer)

* AT BOTTOM OF CHAMBER *

VERTICAL: .4249, .4252, .4250, .4259, .42504, .42502 [.4250, .4252, .4256, .4250]

HORIZONTAL: .4248, .4251, .4251, .4253, .4248, .4248, .4248 [.4252, .4252, .4252]

*10/32" INSIDE CHAMBER* (DIFFICULT TO MEASURE AT THE EXACT SAME LOCATION)

VERTICAL: .4323, .4321 [.4318]

HORIZONTAL: .4320, .4320 [.4318]

*AT CHAMBER EDGE* (DIFFICULT TO MEASURE AT THE EXACT SAME LOCATION)

VERTICAL: .4348, .4343, .4341, .4343 [.4349]

HORIZONTAL: .4343, .4342, .4343 [.4349]

**** 6" BARREL INSIDE DIAMETER **** (measured with telescoping gage and 0-1" micrometer)

BARREL GROVES AT BARREL END (vertical): .4001, .4002, .4004, .4001, .4001, .4002 [.4008, .4005, .4006, .4008]

GROVES: AT BARREL END (horizontal): .4007, .4017, .4004, .4003, .4008, .4006, 4004, .4003, .4001, .4002 [.4005, .4004, .4006, .4004]

LANDS AT BARREL END (vertical): .3899, .3895, .3900, .3890, .3901, .3888, .3894 [.3900, .3903, .3902, .3902, .3902]

LANDS (HORIZONTAL): .3898, .3896, .3900, .3900, .3892, .3897 .3894, .3895 [.3901, .3901, .3903, .3897, .3900]

BARREL GROVES IMMEDIATELY IN FRONT OF CHAMBER (vertical): (groves and lands of tapered, smooth surface are difficult to discern) : .4021, .4020, .4019, .4018 [.4018]

BARREL GROVES JUST IN FRONT OF CHAMBER (horizontal): (groves and lands of tapered, smooth surface are difficult to discern) .4018, .4015, .4018 [.4015]

BARREL LANDS JUST IN FRONT OF CHAMBER (vertical): (groves and lands of tapered, smooth surface are difficult to discern) NONE [ .4005]

BARREL LANDS JUST IN FRONT OF CHAMBER (horizontal): (groves and lands of tapered, smooth surface are difficult to discern) : .3989, .4001 [.4008]

*BOTTOM OF CHAMBER*

VERTICAL: .4241, .4248, .4245, .4250 [.4251, .4253, .4255, .4248, .4250, .4249]

HORIZONTAL: .4248, .4248, .4243, .4244 [.4248, .4248, .4249, .4251]

*10/32" INSIDE CHAMBER* (difficult to measure at the exact same location)

VERTICAL: .4321, .4321 [..4313 ]

HORIZONTAL: .4320, .4320 [.4313]

*AT CHAMBER EDGE* (difficult to measure at the exact same location)

VERTICAL: .4339, .4338 [.4337]

HORIZONTAL: .4338, .4338, .4337 [.4341]

*************** GLOCK FRAME & SLIDE MEASUREMENTS *****************

FORWARD LEFT SLIDE RAIL: (CALIPER) .237, .236, .236, .236, .236, .236 [.235]

FORWARD RIGHT SLIDE RAIL: (CALIPER) .241, .243, .243, .241, .241 [.242]

FORWARD SLIDE TO SLIDE RAIL WIDTH: (CALIPER) .902, .901, .902 [.902 (MICROMETER: .9025, .9026, .9025)] [[159rd.: .9025]]

REARWARD SLIDE TO SLIDE RAIL WIDTH: (CALIPER) .903, .9037. 903 [.9037 (.MICROMETER: .9005, .9010, .9010, .9014, .9011, .9015, .9015, .9014)] [[159rd.: .9013]]

REAR LEFT SLIDE RAIL LENGTH: (CALIPER) .588, .589, .590 [.589] [[159Rd.:MICROMETER .5889, .5888, .5887]]

REAR RIGHT SLIDE RAIL LENGTH: (CALIPER) .589, .590, .589 [.591] [[159Rd.: MICROMETER.5888, .5887, .5885, .5888]]

FRONT RIGHT SLIDE RAIL LENGTH: (CALIPER) .401, ..400, .401 [.401]

FRONT LEFT SLIDE RAIL LENGTH: (CALIPER) .400, .400, .400 [.400]

EJECTOR TIP WIDTH (tip taper prevents consistent measurements): (CALIPER: .0630, .0641, .0646, .0638, .0633 [MICROMETER: .0620, .0618; CALIPER: .063]

SLIDE HOLE DIAMETER (vertical): .6418, .6406, .6406, .6405 [.6403, .6403]

SLIDE HOLE DIAMETER (horizontal): .6354, .6354, .6357 [.6357, .6358]

FIRING PIN REAR LUG WIDTH (LENGTHWISE): (CALIPER) .121, .121 [.120, .120, .119]

FIRING PIN REAR LUG WIDTH (SIDEWAYS): (CALIPER) .155, .152, .152 [.150, .149, .150]

REAR RIGHT SLIDE RAIL GROOVE DEPTH: (CALIPER).107, .1085 [.107, .106, .106]

REAR LEFT SLIDE RAIL GROOVE DEPTH: (CALIPER).109, .110 [.109, .108,]

TOP OF SLIDE WIDTH, IMMEDIATELY IN FRONT OF EJECTION/BREECH: .0977 [.0976]

********************************** G20 PICTURE LISTING **********************************

* TARGETS T1-T22 **

T1: 25 yds.; 6" barrel, Federal 180 gr. JHP

T2: 25 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T3: 25 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core SP

T4: 25 yds.; 4.6" barrel, Federal 180 gr. JHP

T5: 25 yds.; 4.6" barrel, Cor-bon 180 gr. Bonded Core SP

T6: 25 yds.; 4.6" barrel, Cor-bon 200 gr. Penetrator

T7: 25 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T8: 25 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core SP

T9: 25 yds.; 6" barrel, Federal 180 gr. JHP

T10: 25 yds.; 6" barrel, Winchester 175 gr. Silver Tip HP

T11: 50 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core SP

T12: 50 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T13: 50 yds.; 6" barrel, Federal 180 gr. JHP

T14: 50 yds.; 6" barrel, Winchester 175 gr. Silver Tip HP

T15: 50 yds.; 4.6" barrel, Cor-bon 180 gr. Bonded Core SP

T16: 50 yds.; 4.6" barrel, Cor-bon 200 gr. Penetrator

T17: 82 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T18: 82 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core Soft Point

T19: 82 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T20: 82 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core Soft Point

T21: 82 yds.; 6" barrel, Cor-bon 200 gr. Penetrator

T22: 82 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core Soft Point

T23: 100 yds.; 6" barrel, Winchester 175 gr. Silver Tip HP

T24: 100 yds.; 6" barrel, Cor-bon 180 gr. Bonded Core Soft Point

** OTHER PICTURES **

1: AMMO USED

2 - 5: SIGHT ADJUST/REMOVAL TOOL (3 shows the defensive sights)

6: TRU-DOT TOP REAR SIDE VIEW (FOR 2-5 CLARIFICATION)

7: FOURTH ROUND FEED JAM

8 - 9: OEHLER 35 PROOF CHRONOGRAPH W/ PRINTER

10: G20 DISASSEMBLED FOR CLEANING

11: NIGHT SIGHTS VIEWED AT NIGHT

12: NIGHT SIGHTS VIEWED DURING DAY

13 - 14: C5-A ON THE SLIDE RAILS

15: GLOCK W/ HI-CAP MAGS AND 6" BARREL

16: FT. SIGHT (NIGHT SIGHT) ATTACHING BOLT

17-19: RECEIVER ONLY PICTURES

20: BLURRED DEFENSIVE SIGHT

21 - 22: SLIDE, 6" BARREL, AND 4.6" BARREL

23: SHOOTING VIDEO (200KB & 3.5MB)

John Rogers, PMB#107-152, 3267 Bee Caves Rd., Austin, TX 78746

References

Glock Instructions For Use (Form US005 (REV. 2/96)). Available from Glock Inc., 6000 Highlands Parkway, Smyrna, GA 30082.

Tom Graham. (1998, Vol. 4 No.1) Caring For Your Glock. Glock Annual 1998. pp. 66-69.