Glock Pistol Trouble Points

After twenty years of dealing with Glocks my respect for them has grown. I find it a simple, easy to maintain handgun that is among the most reliable service pistols in existence. But, as the number of older pistols grows, and high round count handguns begin to stack up, it is obvious that the Glock isn’t perfect. Nothing on this earth is and the Glock isn’t quite as tough as its adherents claim, though it is probably better than its detractors would like to admit.

The Glock isn’t the easiest pistol to modify or perform custom work on, but it is easy enough to change the sights and springs when needed. A change I caution against is changing the trigger to the 3.5 pound connector. The factory 5.5 pound trigger press is easily learned by shooters that practice and the 3.5 pound connector should be resigned to competition-only handguns. By the same token, the heavier connectors sometimes used by police agencies have no real purpose. True safety is between the ears.

The 3.5 pound connector simply isn’t well suited to a personal defense gun when the user may be winded or excited. The plastic Glock sights are not nearly as rugged as the rest of the pistol. I have seen any number of Glocks with missing front sights and always seem to break when contacting a particularly stiff holster lip. The rear sight is less trouble but still plastic.

When adjusting the Glock sight it is possible to ruin the rear sight as the plastic sight is actually attached to a small metal plate at the bottom of the sight. Be absolutely certain to put the sight adjusting punch at the very bottom of the sight. There are a number of replacement sights for the Glock that do a fine job as combat and competition sights. The Trijicon is currently my favorite. To install this sight, pry the front sight out and place the Trijicon in the opening in the slide.

The screw-on front sight is then installed with a simple driver. Use a little Loctite and you are good to go. The rear sight is driven from the dovetail and the new one bumped in without any problem. These sights offer a better sight picture than the somewhat blocky original sights and are much more durable. Polygonal rifling of the Glock is seen as an advantage by many, which is not cut as deeply in the barrel. Gas seal with jacketed bullets is better with this type of rifling.

Often the Glock will exhibit greater velocity than similar barrel lengths that are conventionally rifled, however, the shallow rifling isn’t compatible with lead bullets. When using lead bullets, the lead often builds up in the grooves of a conventional barrel but there is no where for the lead to go with the polygonal rifled barrel. As a result, pressure can build up quickly and the result is a blown case or even a blown pistol.

Bad news for those shooting in competition or using the Glock extensively need lead bullets for economy. The only answer is an aftermarket barrel. Barrels by Bar-Sto Precision and Wilson Combat have given excellent results in the Glock. The ability to use lead bullets is worth the price of the barrel, however, there are other advantages. These barrels are often more accurate than the Glock factory barrel.

Coupled with more precise sights, the Glock can become a fifty yard pistol rather than a twenty five yard pistol. The Bar-Sto barrel produces at least comparable velocity to factory barrel. In the case of .357 SIG pistols, the Bar-Sto was both faster and more accurate than the factory unit. Gunsmith-fit Glock barrels area worthwhile investment. The pistol’s intrinsic accuracy may be considerably improved. Few chose to fit such barrels but the fact is they offer considerable benefits.

The fitting procedure is simple enough. If the hood is oversize then fit the barrel hood to the slide by carefully removing the barrel sides until the clearance is approximately 0.003 on each side. Take it slowly with the cut and try method. If you are able to fit the barrel with a minimum of tolerance —say, 0.002 on each side—the pistol will be an accurate number. Occasionally, a barrel will bind at the rear of the hood.

Simply pressing the barrel into the slide and working the slide will often fit the barrel, however, if the barrel continues to bind, the rear of the barrel hood must be filed. Use a stone and be certain to bear evenly and finish up with a smooth surface. It is rare for the angled wedge locking surfaces on the bottom of the Glock barrel to need any fitting. When they too the most I have had to work is to slightly file the bottom of the foot. The slide will usually close without any such binding.

As for the rationale for the Glock barrel change, there are three main reasons for fitting a custom barrel to the Glock. First, the ability to use lead bullets. Glock pistols use polygonal rifled bores. The primary difference is that the bore is rifled with hills and valleys that are quite smooth rather than the traditional lands

Even today the Glock is a thoroughly modern handgun. and grooves. This results in little friction and generally higher velocity than conventional bores of a similar length. Accuracy potential is claimed to be high due to the prospect of little bullet deformation. However, there is no place for lead fouling to accumulate. Sport shooters using cast lead bullets for economy cannot use great quantities of lead in the Glock barrel.

There is also the fact that the Glock has a sharp transition from the chamber to the leade or beginning of rifling, which also accumulates lead. This lead build up may prevent the pistol from fully closing and the resulting build up will allow the pistol to fire when not locked up. While the Europeans may think we are mad for using lead bullets, this is the only way for the shooter of average means to afford to fire the piece in the quantity demanded for proficiency in competition.

The Glock barrel as supplied from the factory also has an unsupported chamber in order to insure feed reliability. Almost every aftermarket barrel will offer a more fully supported chamber. Second, Increased accuracy. A custom grade barrel will increase accuracy. This is partly due to careful manufacture and partly due to superior fitting. Lastly, a caliber change. Often a shooter will prefer another caliber or simply wish to use several calibers in their Glock.

You may convert a .357 Glock to .40 and vice versa or convert a .45 ACP Glock to .400 Cor Bon. There are other conversions as well. As for testing the barrel after installation, use good quality factory ammunition. It is difficult to tell a shooter who has spent good money on a custom barrel when his handloads are not up to par. I have taken to keeping a good stock of Fiocchi ball ammunition for this purpose. I use the 124 grain 9mm, 180 grain .40 and 230 grain .45 ACP.

I proof the handgun with these ball loads before progressing to lead loads or hollow point loads. Once the pistol is proofed with these loads, a malfunction with handloads is ammunition related. That being said, handloads may be produced that are at least as reliable as and more versatile than factory loads—once the pistol is proofed. Recently, I worked with a .40 caliber Glock that simply would not function with any standard handload.

I was using the proven Zero Bullets 165 grain FMJ over enough Tite Group powder in Starline brass exiting at 900 feet per second. The new barrel seemed to be fitted OK, but the problem was insidious. About every tenth round would not properly cycle. The shooter had dropped the overall length of the cartridge and he assured me he was within safe pressure limits but the problem remained. Far The grip frame has been modified for better hand fit and the frame NP3 coated by Robbie Barkmann at Robar.

The bullet taper cannot be allowed to breach the cartridge case mouth and deep seating bullets is counter intuitive to feed reliability. Manually operated the cartridges fed fine. The cartridges passed not only the Brownells Go/No Go gauge but they fit perfectly when dropped into the barrel. When the barrel was tilted they still worked as far as chambering. Some of the failures presented the bullet nose at a thirty degree angle to the barrel chamber.

Yet every time the slide was manually racked the loads functioned. I made certain the spring was a full power Glock recoil spring—it was. A possibility was that the pickup rail picked the cartridge up at the extractor groove rather than the rim. This would result in the cartridge not getting a full travel. While a good bet, this hypothesis did not pan out. Often a high capacity magazine that extends past the grip frame will give trouble but this was not the case either.

I did another firing test with a slightly different load and encountered the same problem except that now the cartridge did not always feed when I dropped the slide manually. By holding the slide a bit further to the rear and releasing the slide, the rounds fed every time. With all else failing to resolve the issue, I decided to address the chamber. As it turned out, certain dimensions were tighter than the original Glock barrel.

In the end I carefully polished a rounded edge from two o’clock to ten o’clock on the chamber. I hit pay dirt with this one. The Glock ran smartly after this simple polish. Another drop in barrel gave considerably more trouble. Perhaps it was a gunsmith fit barrel that was mistakenly packaged in a drop in pack! Glock frames are the same internally without fail through all generations—they claim—so the fault must have been in the barrel.

Just the same, several holster makers tell me you have to know the Glock generation to get a properly fitted holster, although this does not mean anything internally. The hood of the suspect barrel presented no problem but the rear lug struck the frame lock bar. I proceeded to cautiously mill and file

This one is from Wilson Combat. and then stone the lug. I removed 0.016 off the rear lug and it then cleared the lock bar. I did not like the amount of work needed on this drop in barrel but it worked. Another experience was with a .357 SIG barrel from Bar-Sto Precision. This barrel was an eye opener. The primary purpose of this barrel was the owner’s wish to experiment with the .357 SIG, back when the cartridge was new and there were no factory Glock pistols chambered in it.

The Bar-Sto barrel was a drop in without any sort of fitting. However, we were very surprised at both the accuracy and velocity results. The first Cor Bon loads fired clocked 1503 fps with a 115 grain bullet. Accuracy was excellent. We fitted Novak aftermarket sights and the pistol often grouped five shots into less than two inches at twenty five yards, a far cry from the four inches plus at 25 yard groups with .40 factory ammunition.

I did have to fit a heavy duty WC Wolff recoil spring to preserve cycle reliability. The .400 Cor Bon conversion in a .45 Glock was uneventful as well. I have done only one but this was simply a drop in conversion. There were no problems and the pistol simply ran as well as with the .45 ACP loads. Remember, when fitting a .400 Cor Bon barrel to a 1911 you may have to open the feed lips of the magazine. This would not have been possible with the Glock. The Glock ran fine. They are anything but rugged.

Barrel Fitting Procedures I first drop the barrel in the slide and frame. If the barrel does not fit correctly it is most often the barrel lugs binding. I remove very small amounts of metal from the hood area and then check to see if the under lug is perpendicular to the bore as it should be. If off center, material is removed from the opposite of the offending side. Look toward the muzzle to gauge right and left alignment of the locking lugs. Off to the left, remove metal on the right.

When done with the lugs, place the barrel

into the slide and check for fit. Remember to respect the locking lugs as they control lift and chambering angle. The bottom foot controls lift and usually gives a good tight lockup without any type of modification. The Glock is a straightforward pistol, simple enough to work with and durable. The only common reason that you will see a Glock in the shop is for barrel work or changes. This is the most beneficial change to the Glock pistol. Approaching the Glock trigger action must be done with caution.

The standard trigger action is certainly combat worthy and should not be changed if the pistol is used for personal defense. You cannot stone the action or apply Tetra Lube to lighten it. This is truly a different type of pistol. The connector is the drawbar of the Glock as it serves much the same purpose as the drawbar on a double action pistol. To replace the connector, field strip the Glock and remove the trigger mechanism out from the polymer frame.

The tail of the connector connects to the trigger block and is pushed out from the opposite side of the frame in which it rests. Then, simply replace the new connector into its place. You will see that the new, lighter connector offers a lighter action, primarily by changing the angle of the trigger press and leverage of the trigger pull. Remember, the heavier trigger action on some service Glocks is a product of a heavier trigger return spring and not the connector.

At the present, no reason for the blow at right, fired in a Glock Model 37, is known for certain. Note distinctive Glock firing pin indent. Another gimmick for competition guns is the lightweight striker. This doesn’t lighten the trigger action but since the new striker is lighter than the steel striker, lock time is faster. However, caution must be observed as the lighter strike just may not ignite every primer of every military, defense and surplus round. Better a heavy strike in a service pistols.

A police armorer will tell you that the 9mm Glock rarely shows excess wear but the .40 caliber Glock often shows the impact of the heavy momentum of the cartridge. There are

a few spots that are likely to wear on the Glock. Some, perhaps, were subjected to too many hot loads but we never know. We only know the problem. One of these problems is a peened or damaged firing pin channel. This is usually the result of primer set back or heavy loads. The striker usually works just fine. The problem is that the cartridge will drag on this rough part of the breech face and cause a drag during cycling. The cure for this problem is simply to carefully polish the breech face.

This may not eliminate erosion but it does restore function. Glock Safety Check A good preliminary check is to press the striker forward and be certain that the firing pin block or drop safety keeps the striker from running forward. With the slide removed, check the trigger safety. Move the trigger bar forward. The safety should click into position. Then pull the trigger and ease the Complete your American Gunsmith collection. Or read up on a special subject! A limited number of the following