The Ultimate Firearms Destination for the Gun Lifestyle

AR-15 and Glock 17 Cheap DIY Upgrades

At RECOIL, we review every product fairly and without bias. Making a purchase through one of our links may earn us a small commission, and helps support independent gun reviews. Learn More

DIY Upgrades for Your AR and Glock

In a world of custom, John Wick-inspired, lightened, and Cerakoted rifles and pistols, price tags can exceed a few mortgage payments. For those who work for a living or live with a spouse’s watchful eye, we decided to make budget-friendly upgrades to an affordably priced DPMS AR-15 carbine and a second-hand Glock pistol. Rather than making Gucci guns, we worked to enhance the performance of both platforms without breaking the bank.

The AR in AR-15 originally meant Armalite Rifle; some would say it now stands for America’s Rifle due to the millions of AR-15 based rifles now in circulation. The proliferation of the AR-15 design has resulted in rifles ranging from inexpensive to several grand. We chose a brand-new, value-priced DPMS to upgrade.

And if the AR-15 is America’s Rifle, Glock has created the universal pistol. Found in every corner of the world, Glocks are known for their reliability and ability to perform when needed for duty, competitive, or defensive uses.

Before making changes, we performed baseline testing on both guns to determine the effectiveness of our upgrades. We tested accuracy by shooting different types of ammunition at known distances. Shooting performance was tested with a variety of drills incorporating multiple targets of different sizes, different target distances, movement, and reloads.

The DPMS delivered 3 to 5 MOA performance from a variety of ammo, with some heavier match ammunition performing a little better. The Glock ran well and could be shot decently, but the sights held the pistol back. With prior use breaking in the gun, the trigger was smooth, although a little heavy, in stock configuration. Both rifle and pistol showed promise but could use some upgrades.

The upgrades we applied to our basic-bitch AR-15 saw group sizes shrink by nearly half from it's original 3-5 MOA sized groups.

The Carbine
Starting as a weapons parts manufacturer in the mid 1980s, Defense Procurement Manufacturing Services (DPMS) became a large player in the AR-15 world. Our base carbine for this project was the LCAR model, a simple Mil-spec-type carbine that looks similar to a military M4.

The AR-15 platform is highly modular, enabling a variety of upgrades and modifications. We made changes to help a shooter deliver more accurate rounds on target quickly. To do this, we upgraded the handguard, switched to an adjustable gas block, installed a nicer trigger, added a muzzle brake, and changed the furniture.

Getting rid of the M4-style gas block with its integrated sight tower and replacing it with a low-profile gas block allows the use of a slim, free-float handguard that improves handling and accuracy.

Handguard and Gas Block
Replacing a stock handguard with an extended rail offers numerous benefits, including better ergonomics for shooting the rifle, better airflow for cooling, the ability to bolt on accessories, and a free-floated barrel for some models. For the tightest budgets, a drop-in handguard replacement doesn’t require changing the barrel nut but might not free-float the barrel. If you’re on a budget and/or don’t have the tools to do a whole free-float rail upgrade, there are handguards that use the GI barrel nut. The only challenge is you’ll have to hacksaw or Dremel off the front sight to provide clearance for the rail.

M4-style handguards that have a delta ring barrel nut (top) require a common armorers wrench, but your replacement handguard may use a proprietary barrel nut and require the use of a matching, proprietary tool (bottom).

We wanted all the benefits, particularly free-floating the barrel to increase our accuracy potential. Free-floating removes contact with the handguard to eliminate interference with barrel harmonics. This increases consistency as well as accuracy and reduces point of impact shift when you place the handguard against something like a barricade.

We selected a 14-inch Midwest Industries Slim Line rail. To install it, we had to either cut down the front sight block to fit under the rail or replace it with a low-profile gas block. Doing the latter with an adjustable piece would also allow us to reduce the gas flow and tune the gun for reliability. With short gas tube lengths on carbines, too much gas pressure increases the bolt carrier speed, harming reliability and increasing recoil unnecessarily. Thus, we installed an adjustable gas block from Seekins Precision in Idaho.

The rail installation involves removing the muzzle device, front sight base, and original barrel nut. An armorer’s wrench such Magpul’s has the appropriately sized cuts and surfaces to do the job correctly. Installing and torqueing the rail-specific barrel nut is next, followed by installing the new gas block. Take care to ensure the gas block and tube are installed and aligned correctly.

Mil-spec AR triggers were designed for reliability and functionality on a combat rifle. While reliable, they’re usually handicapped by a heavy and gritty trigger pull. Our DPMS’s stock trigger was no different, breaking inconsistently between six and seven pounds. Even though the AR’s better than some other military rifles, a lighter trigger with a clean break can allow for faster and more precise work. Rock River Arms has been offering solid rifles and parts at affordable prices for many years. Their national match trigger is an affordable and reliable two-stage unit and has been a popular choice within the service rifle community.

If you’re lucky, swapping your AR’s trigger only involves a couple pins and a little swearing while lining up the internals. Some trigger swaps require the removal of the safety.

Installation is very simple, starting with removing the original trigger. With a punch, first drift out the hammer pin and remove the hammer assembly. Then, remove the trigger pin, trigger, and disconnector. Install the Rock River trigger by following these steps in reverse. Beware to install the springs in the correct orientation for proper function, and note that some lowers might require removal of the safety. Our new trigger broke at approximately four pounds, with a defined first and second stage and a crisp reset.

Muzzle Brake
Muzzle brakes are used to tame recoil on weapons platforms from cannons to rifles. The DPMS came adorned with a standard A2 flash suppressor. While effective at disrupting gases to reduce flash during firing, it doesn’t redirect these gases for recoil control. A 5.56mm rifle isn’t a heavy-recoiling rifle by any means, but a muzzle brake aids in getting rounds on target faster.

Within their parts catalog, DPMS offers the Miculek brake, originally designed for competitive shooting. While an older design, it’s very effective at reducing recoil without breaking the bank. Designed with Jerry Miculek, one of the fastest action shooters in the world, the brake has three ports per side to direct gases for reducing recoil. The consequence of this is increased noise and concussion. However, for going fast without muzzle climb, a muzzle brake is the solution.

Upgrading the most basic handguards generally require swapping the barrel nut, but the new part makes a huge difference in handling, modularity, and possibly accuracy.

Our rifle came with very simple Mil-spec-type furniture. Unless you’ve been living under a rock, you’ve probably heard of a little company called Magpul. Originally started with a magazine pull to easily remove magazines from pouches, Magpul has grown to be an industry leader with parts, accessories, and lifestyle products for shooters. While we didn’t change anything mechanical, upgrading the furniture made the rifle more ergonomic for shooting and manipulations.

We replaced the original buttstock and pistol grip with MOE-SL replacements, and the trigger guard with an MOE piece. Additionally, we added the Type 2 M-LOK rail covers to the handguard. All these accessories are made of polymer to save weight while remaining durable. The grip and panels are textured to help hold onto the rifle in any condition, while the grip angle and stock shape offer greater comfort and better fit with the carbine.

The Pistol
For the past several decades, Glock pistols have walked the beat with more law enforcement agencies than any other. As pistols retire from service, they’re generally traded-in and resold to the commercial market. The average street price of a new Glock can range between $450 to $600, but many used models can be found for as low as $250 to $300. As former police guns, most have been carried a lot and shot a little. This means most second-hand Glocks still have plenty of life left in them.

The base gun for our project was a well-used Gen 3 Glock 17 in 9mm. We chose to breathe new life into the old gun with upgraded sights, trigger, barrel, magwell, and new magazines.

Generally, every stock Glock will see a performance benefit when upgrading several common parts, namely the trigger, barrel, and magazine well.

Replacing the sights should be the first order of business for any Glock owner, as the OEM sights are made of plastic and suck. For a defensive-oriented pistol, consider at least a front night sight or “straight-8” design with tritium vials to provide visibility in low-light situations. For competitive shooting or just having fun on the range, a fiber-optic front sight transmits ambient light to the end of the fiber for fast and easy sight acquisition. My preference in sights for over the last 10 years has been Warren Tactical Sights.

Designed by Scott Warren, a former FBI Hostage Rescue Team member and successful competitive shooter, his sights have a unique wave shape to the rear sight. The center is a U-shaped notch with 90-degree angles at the top-inside edges for alignment with the front sight, while concave corners open up the field of view of the target and surrounding area The lack of hard angles allows your eye to quickly find and focus on the front sight, yet deliver the precision needed for proper sight alignment. Finally, the front face of the sight is cut to allow for one-handed manipulations.

Glock front sight posts are screwed in through the slide and easily changed with a screwdriver. Newer models require a shallow nut driver that’s found with a Google search for “glock front sight tool.”

Changing the sights on a Glock is straightforward. The front sight is held in place with a screw; be sure that the new front sight is straight in the cutout when you install it. The rear sight requires a sight tool or use of a hammer and punch to remove the old sight and install the new one. When installing it, center the sight in the dovetail, and if necessary, make slight adjustments after you shoot it.

Trigger Kit
Stock Glock triggers are advertised at 5.5 pounds of pull weight, although most tend to have a heavier trigger. Without going crazy for some of the full kits available, we picked up a ZEV Professional Starter Spring Kit for $29. This kit includes a replacement striker spring, firing pin safety spring, trigger return spring, and connector. The lighter springs reduce resistance on the firing components, while the connector alters the geometry of the trigger operation to provide better trigger feel and further lighten the trigger pull.

There aren’t many parts in a Glock to begin with, and the ones that make the most difference are easily swapped for aftermarket parts. Highly polished parts make trigger pulls smoother and small changes in trigger connector geometry reduce trigger pull weights.

Replacing the trigger parts isn’t hard, but if you haven’t done it before it might seem complicated. A Glock armorer can replace these parts in their sleep but for the uninitiated, the process can be found online. The slide assembly is also simple to take-down once you’ve seen it done, just beware to not lose any parts and ensure installation is done correctly. We’ve also outlined these steps in Issue 14’s DIY column.

Since our second-hand Glock had been used heavily, the parts were worn in nicely. The trigger had smooth take-up and a positive wall, breaking at 6 pounds. The upgraded trigger was still smooth, while the new connector dropped the weight to 4.5 pounds. The wall before the break was also lighter and crisper.

Factory Glock barrels are hammer-forged and known for being a good barrel capable of shooting a variety of ammo with a long life. Replacing the barrel isn’t always necessary if the pistol wasn’t shot a lot. However, if you’re interested in chasing accuracy or adding a suppressor or compensator, a barrel replacement might be right for you. Additionally, if you happen upon a screaming deal for a .40 S&W but wanted a 9mm, there are drop-in caliber conversion barrels.

The only thing easier than upgrading a Glock’s barrel is changing the magazine.

We obtained one from SilencerCo, which offers high-quality drop-in barrels for a variety of pistols, including Glocks. These barrels are made of 416R stainless steel (common in many match barrels) and finished in black nitride for extra hardness. The muzzle is extended and threaded for mounting a suppressor or muzzle brake with U.S. and metric threads, depending on your attachment of choice. Replacing the barrel is as easy as field stripping the pistol and swapping in the new part.

Magwell and Magazines
In 2015, Magpul announced their first Glock accessories, including a magwell and 9mm magazines. When shooting pistols, being able to rapidly reload allows a shooter to stay in a fight, in the game, or get shooting faster on the range. A magwell aids this by providing an expanded opening at the bottom of the frame. This increased diameter is more forgiving, especially when going fast, and a magazine might not always be perfectly aligned. Some competition magwells can be quite large, but Magpul created a streamlined unit that can be used on a carry or competition gun. Installation was as simple as placing the unit over the magwell opening and tightening down the supplied screw.

Adding a magwell funnel to your pistol decreases the accuracy needed when slamming a mag home and increases the speed you can reload. They’re generally cheap and easy to install.

Magazines are often the weak point to any firearm, whether it’s a good magazine at high cost or a magazine that simply doesn’t work reliably. Glock offers a good polymer molded magazine with a metal liner. However, if on a tight budget, Magpul offers a variety of polymer magazines that are lighter in weight and inexpensive. Retail price is around $40 for OEM Glock mags, while the Magpul options start at just $12.50. We picked up three flush-fitting 17-rd and three extended 21-rd magazines for the equivalent of two OEM magazines.

Final Testing
Once we completed our swapping of parts and garage gunsmithing, we wanted to see how much of a difference we actually made. Running the same drills as our baseline tests, we found both guns had changed. The rifle saw noticeable performance changes for the better, with group sizes shrinking by nearly half from its original 3-5 MOA sized groups. Pistol accuracy improved with the fresh barrel, but it wasn’t as drastic. With an assortment of FMJ practice and JHP duty ammo, the OEM barrel delivered 4- to 5-inch 10-shot groups at 15 yards, while the SilencerCo replacement was tighter at 2.5 to 3.5 inches on average.

As far as the ability to apply accurate fire under speed, both guns showed big changes on the timer and by feel. With the rifle, we ran El Presidente drills from low-ready as well as a 100-yard drill consisting of 5-shots from standing, kneeling, and prone. El Presidente times improved by 25 to 30 percent, while the 100-yard drill went from A- and C-zone hits in almost 25 seconds to almost all A-zone hits in 15 seconds. While louder to the shooter, the muzzle stayed flat on the target rather than bouncing around and requiring more time to re-aim. The trigger was significantly nicer than the stock unit, allowing faster splits between shots and greater accuracy at high speed with the crisper break. Finally, the longer handguard increased leverage by allowing the support hand to grasp it further forward, while the more ergonomic furniture made the gun handle that much better as well.

$502 invested in our DPMS AR netted a 2-MOA increase in accuracy and noticeably faster split times. Optics are outside the scope of this article, but we used the pictured Nightforce to evaluate performance before and after our upgrades. $396 invested in our stock Glock netted less drastic performance improvements, but we did notice reduced split times and faster reloads.

The pistol performance gain wasn’t as great as with the rifle, but the changes brought the heavily used gun back to life. We ran several iterations of the El Presidente and other similar drills with draw, multiple shots, and reloads. We found the most noticeable change came with the new sights. The factory sights were hard to shoot accurately and obscured much of the target. Going to a thinner front sight with a fiber dot and having more of the target in view made target acquisition faster, while also allowing greater precision. The trigger upgrade was noticeable, also helping with precision and speed. On a double-stack gun, the magwell was a nice addition but not as noticeable of a change on the timer. On average, the upgrades resulted in tighter accuracy and shaved 10- to 20-percent off of the recorded drill times, with noticeable increases in speed for first round hits and reloads, indicative of the better sights and larger magwell. The original Glock factory barrel wasn’t quite ready to retire quite yet … but the SilencerCo barrel tightened up the groups. We didn’t accuracy test with a suppressor, but the ability to go quiet put a big smile on our face.

Midwest Industries Slim Line – 14-inch Rail: $155
Seekins Precision Adjustable Gas Block: $59
Rock River Arms Trigger: $120
DPMS Miculek Muzzle Brake: $40
Magpul MOE-SL Stock: $60
Magpul MOE-SL Grip: $20
Magpul MOE Trigger Guard: $9
Magpul M-LOK Rail Covers – Type 2 (quantity 3): $39
Total: $502

Warren Tactical Sights – Fiber Optic Front: $77
Zev Professional Starter Spring Kit: $29
SilencerCo Barrel: $190
Magpul Magwell: $25
Magpul Magazines (quantity 6): $75
Total: $396

Enter Your E-Mail to Receieve a Free 50-Target Pack from RECOIL!

NEXT STEP: Download Your Free Target Pack from RECOIL

For years, RECOIL magazine has treated its readers to a full-size (sometimes full color!) shooting target tucked into each big issue. Now we've compiled over 50 of our most popular targets into this one digital PDF download. From handgun drills to AR-15 practice, these 50+ targets have you covered. Print off as many as you like (ammo not included).

Get your pack of 50 Print-at-Home targets when you subscribe to the RECOIL email newsletter. We'll send you weekly updates on guns, gear, industry news, and special offers from leading manufacturers - your guide to the firearms lifestyle.

You want this. Trust Us.

Add a comment

Your email address will not be published. Required fields are marked *

Subscribe to the Free