Handguns > Semi-Auto

Upgrading Your Glock

With the right equipment, you can build an entire Glock pistol from scratch.


For the past three years, one type of gun has dominated the equipment list at the Int’l Defensive Pistol Ass’n National Championships. IDPA collects a detailed equipment survey of all the shooters in attendance at each National, and the numbers don’t lie. The Glock reigns supreme. In fact, Glock pistols have become so popular that it is now entirely possible to build an entire “Glock” from the ground up that uses no actual Glock parts whatsoever. While that’s rare, what is common is for shooters to take their factory Glocks and improve “perfection” a little bit by adding a part here or a part there.

The two most popular models of the Austrian pistol for competition shooting are the Glock 34 and Glock 35. Chambered in 9 mm Luger and .40 S&W respectively, both the 34 and the 35 received the Gen 4 upgrade treatment as well. On the Gen 4 Glock 35, shooters get removable backstraps, adjustable sights, a reversible magazine release button and, of course, Glock’s new captive dual-recoil spring assembly, designed to help tame the sharp recoil of the .40 S&W cartridge. Thanks to the demands of competition shooters who rarely leave their guns stock, there exists a tremendous amount of aftermarket support for the Glock 35. Shooters will tune their Glocks to a high degree using such parts in order to eke out every last ounce of performance possible.

Usually, the first modification to a Glock is to remove the factory sights. Coincidentally, the Gen 4 Glock 35 received for this article arrived the same day a box from 10-8 Performance showed up. That box contained a set of 10-8’s excellent Glock sights, which feature a U-shaped rear notch and a fiber-optic front sight. With the new sights installed, the sight picture on the Glock 35 is crisp and clean. The wide U-shaped notch of the rear sight allows plenty of light around the front sight post. The fiber-optic rod on the front post gathers light, aiding the eye in the task of quickly acquiring the front sight to break a shot. Many shooters are happy once they upgrade the sights, but for those who want more there are nearly endless Glock modifications.

Proceeding in a logical manner, the next set of modifications is to the trigger pull. The Glock 35 comes from the factory with what measured out to about a 4.5-pound trigger. In models such as the 17 and 22, it is very common to replace the stock trigger connector bar with a 3.5-pound connector; however the Glock 35 already has Glock’s version of that lightened connector. Even so, Lone Wolf and Glockworx both make aftermarket 3.5-pound connectors, which will smooth and improve the Glock 35’s trigger pull. Adding an aftermarket connector is step one in lightening and smoothing the trigger pull.

Step two is to replace the firing pin/striker spring with a lighter weight spring. Because the Glock’s safe-action trigger mechanism only partially cocks the striker when the gun cycles, pulling the trigger to the rear completes the action of compressing the striker spring before it is released. Changing to a lighter striker spring will lower the weight of the trigger pull. With an aftermarket 3.5-pound connector and a 4-pound striker spring, the Glock 35 now has a trigger pull less than 3.5 pounds. Unfortunately, reducing the weight of the striker spring means that the firing pin itself has less velocity when it is driven forward. This can lead to light primer hits, an undesirable outcome in the middle of a match.

Firing pin velocity can be increased slightly by replacing the factory part with one that is skeletonized and, therefore, lighter in weight. Multiple companies make lightweight firing pins for Glocks. Some use titanium, and others use steel with circular lightening cuts in the body. Either method has the same result—restoring reliable ignition. With that in mind, however, the minute that the firing pin and spring are modified, the Glock 35 becomes a competition-only gun. It is not suitable for personal protection with the trigger pull hovering around 3 pounds. It is also advisable to try and stick with ammunition that employs softer primers once the trigger modifications are complete. Federal primers will give your race-Glock the best chance for reliable ignition.

The next stop on the whirlwind modification tour is the recoil spring assembly. The Gen 4 Glock 35 uses Glock’s new captive dual-recoil-spring assembly. It helps reduce the felt recoil of .40 S&W rounds, and is perfectly acceptable in its stock configuration. But “acceptable” is not the goal here—performance is. There are really only two options for modifying the recoil spring assembly in a Gen 4 Glock 35. The first is to buy a new dual spring captive system, but with a body made from steel or tungsten. That adds weight to the front of the gun, reducing muzzle flip between shots. The folks at www.glockstore.com make an excellent tungsten recoil spring assembly for the Gen 4 Glock 35. Unfortunately, with the captive systems the gun is still stuck with the factory spring rates. There is a modification for that in the form of an adaptor, which allows the use of Gen 3 recoil systems on Gen 4 guns. It is simple: The adapter fits in the oversize plug on the front of the slide, and the Gen 3-style guide rod and spring interact with it the same way they would a regular Gen 3 slide. That means lower spring rates are available for the Gen 4 Glock 35. Shooting full-power .40 S&W ammunition can get a little bit tiresome after an extended range session, and light competition/target loads frequently won’t cycle the heavily sprung Gen 4 guns. By changing out the Gen 4 recoil spring assembly for an adapter and a lighter spring on a steel Gen 3-style guide rod, the Glock 35 will then cycle everything from light, 125-grain frangible ammunition up to 180-grain jacketed hollow-points that meet the ground level requirements for major power factor.


Even then, shooting a lot of .40 S&W can get expensive, so the last modification for the top half of the gun is a whole new barrel. Lone Wolf makes a 40-9 conversion barrel. Just take the factory Glock .40 S&W barrel, drop in the Lone Wolf 9 mm Luger barrel, and the Glock 35 will run the comparatively less expensive 9 mm rounds. Since the recoil spring has already been lightened, function won’t be affected by going to the lower-pressure cartridge. To complete the job, there are even full-on aftermarket slide and barrel combinations.

Now that the top half of the gun has been thoroughly modified, it’s time to start making changes to the frame. The most drastic change possible is a complete replacement of the entire frame. Lone Wolf makes a Glock replacement frame called the Timber Wolf. As of this writing, it’s not yet compatible with the Gen 4 guns, but that should be coming soon. Sticking with the factory Glock 35 frame, there are a number of parts to change. The first thing to go was the connector mentioned earlier. It only makes sense to follow that up by dropping in an entire new trigger kit from Glock Triggers. The company’s Edge trigger kit replaces the entire trigger assembly of the Glock 35—connector, trigger bar, the trigger itself and even the ejector. Take the current unit out, drop the Edge in. The trigger pull on the Gen 4 Glock 35 is then smooth with a much crisper break point and a positive reset, still measuring around 3 pounds.

A great functional modification for the slide stop lever starts with removing the factory Glock extended lever. Shooters with large hands frequently will bump the extended Glock lever during rapid shooting, prematurely locking the gun open before the magazine is empty. A factory-length slide stop from a Glock 17/22 will fix this, but there’s an even better aftermarket part out there. The Vicker’s Tactical slide stop is the same length as the Glock 17 slide stop, so it won’t be accidentally engaged during recoil like the factory extended model. Where it shines in comparison to the factory standard model is that it has more lateral surface area. It does protrude from the side of the gun ever so slightly more than the factory standard slide stop, and that distance makes it perfect for executing slidelock reloads by hitting the slide stop with the strong hand thumb. To add a bit of visual appeal to the gun, there are also stainless-steel pin kits available. They replace the black Glock pins, giving the gun a bit of two-tone bling.

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8 Responses to Upgrading Your Glock

blaize wrote:
September 27, 2014

Trijicon is the most popular I use them personally on my glock model 22..no complaints

Leslie wrote:
June 16, 2013

Ihave a glock 17,i would like to know,which night sight is the best one to use for replacing the sight that comes with the g3.

Rob wrote:
June 12, 2013

The most popular mod i know of was not mentioned. 'Stippling', if stock or full open gun, stippling is a must!

Hutch wrote:
February 15, 2013

I agree, none of these parts are required to make a Glock function or be reliable, to the contrary I've yet to see any after market parts that increase reliability and those that claim to increase performance are often only minor improvements if any at all. The best thing you can do is take your Glock tool or save $7 and just get a 3/32 punch, which the Glock tool is an do a nice light polish on the trigger components. See 25 cent trigger job on YouTube.

MattS wrote:
February 06, 2013

Great article except for 1 thing. The author implies that all these mods only cost $8 (for the take down tool). He fails to mention how much a Zev Tech trigger costs, let alone the flared magwell, firing pin and custom sights. For a beginner competitor they might read this article and want to do every single mod only to find out it costs more than $8. The G34/35 shoot great outa the box but you can do cheap mods to make it slightly better while sticking to Production legal. Maybe the author should've mentioned these simple, cheap alternatives to a class of reader that is trying to save money in this economy.

Richie wrote:
January 31, 2013

LOnz, you don't have to replace anything to make the gun "function." The gun works just fine out of the box. The article refers to optional modifications competitive shooters make to adapt the gun to their particular needs. Match winners seldom shoot stock guns, which are compromises.

Greg wrote:
January 30, 2013

I just bought two 34's and my son and I shot them stock as a rock at our first IPSC match and they performed great. You don't need to pay hundreds to have fun. Just go out and shoot.

Lonz wrote:
January 30, 2013

Why buy the gun in the first place if you have to practically replace all the major parts to make it function? Re-read the article and see how many components need swapped out. Is it really worth buying it in the first place?