The Glock 34 is Glock’s long-slide 9mm built for one thing: shooting well. Its extended barrel and slide, longer sight radius, and factory optics-ready MOS cut make it a favorite of competition shooters and a mainstay on SWAT teams. Because it is already a purpose-built performance gun, a Glock 34 build is about sharpening the edge — a red dot, competition sights, a tuned trigger, and the mag extensions that keep you in the stage.
Below are the Glock 34 parts and accessories we would add first, geared toward competition and range performance but useful for duty too. These fit the Gen 3, Gen 4, and Gen 5 Glock 34 (many parts interchange with the Glock 17) unless noted, and each pick is backed by a live price check across the retailers we track.
How we tested: Every pick here was run through our testing methodology. Minimum round counts, accuracy and reliability protocols, the failures that disqualify a gun. If we haven't shot it, we don't recommend it.
Glock 34 Upgrades at a Glance
| Category | Our Pick | Why It Makes the List |
|---|---|---|
| Red dot optic | Holosun 507C | The single biggest speed upgrade on the MOS slide |
| Trigger | Overwatch Precision DAT | Flat face, cleaner break for faster splits |
| Sights | Night Fision | A bright front and suppressor/co-witness heights |
| Barrel | Faxon / factory | Match accuracy, threaded options for a can |
| Magazine | Magpul PMAG GL9 | Reliable 17-round capacity |
| Magazine extension | Taran Tactical | More rounds and a flared base for competition |
| Weapon light | Streamlight TLR-7 | Slim 500-lumen light for the full-size rail |
| Holster | Molded Kydex | Competition or duty retention with a clean draw |
Best Red Dot Optic: Holosun 507C
The Glock 34 MOS was made for a red dot, and adding one is the single biggest hit-probability and speed upgrade you can make on this gun. The Holosun 507C is the value benchmark: a rugged open reflex with shake-awake, a multi-reticle system, a solar backup, and years of battery life, mounted on the correct MOS plate. Its long slide gives you a rock-steady platform for the dot. Co-witness it with suppressor-height irons for a backup.
For more optic options and how to choose, see our best pistol red dots guide.
Best Trigger: Overwatch Precision DAT
A competition gun lives on its trigger. A flat-faced drop-in like the Overwatch Precision DAT gives you a more consistent finger placement, a cleaner wall, and a crisper break for faster, more accurate splits — all without touching the gun’s safeties. It installs in minutes and is one of the upgrades you feel on the very first stage.
Best Sights: Night Fision
The Glock 34’s long sight radius rewards good sights. A Night Fision set gives you a bright, fast front-sight pickup and is offered in suppressor and optic co-witness heights, so it works whether you run irons or back up a red dot. Whether you prefer tritium for low light or a fiber front for daylight speed, upgrading from the factory plastic sights is a cheap, high-value change.
Best Barrel: True Precision
A match-grade drop-in barrel tightens groups, adds a supported chamber for reloaders, and — in threaded form — lets you run a compensator or suppressor on the long slide. Match barrels from Faxon and a factory Glock threaded barrel are proven, well-priced options with excellent rifling. Match the thread pitch to your can or comp if you go threaded.
Best Magazine: Magpul PMAG GL9
You can never have too many magazines on a competition gun. The Magpul PMAG GL9 gives you reliable 17-round capacity at a fair price, and factory Glock 17-round mags are the other proven option. Buy plenty for practice and matches, and see the next section for adding rounds with an extension.
Best Magazine Extension: Taran Tactical
Running the Glock 34 in USPSA or 3-gun? A Taran Tactical (TTI) magazine extension adds several rounds and a flared, positive base that speeds reloads and helps seat the mag hard. TTI base pads are a competition standard for exactly this reason — more rounds in the gun means fewer reloads on the clock.
Best Weapon Light: Streamlight TLR-7
If your Glock 34 pulls duty or home-defense duty alongside the range, add a light. The Streamlight TLR-7 is the slim-body standard at 500 lumens, with a compact head that clears most holsters, ambidextrous switching, and a price that undercuts the SureFire alternative. The full-size frame has plenty of rail to mount it. Buy a holster molded for a light-bearing gun once you do.
Best Holster: Molded Kydex
The right holster is what makes the Glock 34 work in its element. A molded Kydex holster made for the long-slide 34 gives you secure retention and a clean, consistent draw, whether you run a competition OWB rig or a duty holster. Match it to your exact configuration — bare gun, light-bearing, or optics-cut — because a universal holster costs you time and consistency.
How to Prioritize Your Glock 34 Build
The Glock 34 is built to shoot, so upgrade to sharpen its performance:
- A red dot first. The MOS slide was made for it, and nothing improves speed and hit probability more.
- A trigger and sights. A cleaner break and a fast front sight are where you win or lose splits.
- Magazines and extensions. Capacity and fast reloads keep you in the stage.
- A match barrel and a light to chase accuracy, run a suppressor, or add a duty role.
Want the background on the gun first? Read our Glock 34 Gen 5 MOS review, then see how it fits the field in our best competition pistols, best Glock pistols, and best full-size 9mm pistols roundups. Don’t forget quality 9mm ammo to feed it.
Frequently Asked Questions
What is the best upgrade for a Glock 34?
A red dot. The Glock 34 MOS slide is built to mount an optic without machining, and a quality pistol dot like the Holosun 507C is the single biggest speed and hit-probability upgrade you can make on a competition or performance gun. A tuned trigger and good sights are the next priorities.
Is the Glock 34 optics ready?
The Glock 34 MOS (Modular Optic System) models ship with a slide milled to accept popular red dots via an adapter-plate system, no custom machining required. Non-MOS Glock 34 slides require a gunsmith to cut them for an optic. Confirm your specific model and use the correct MOS plate for your chosen dot.
Do Glock 34 and Glock 17 parts interchange?
Many do. The Glock 34 shares the Glock 17's frame and much of its internal parts, so triggers, magazines, sights, and small parts generally interchange. The slide and barrel are longer on the 34, so slide- and barrel-specific parts are not cross-compatible. Always confirm a part is listed for the Glock 34 where length matters.
How many rounds does a Glock 34 magazine hold?
The Glock 34 uses standard Glock 9mm magazines, holding 17 rounds in a flush factory mag and more with extended magazines or aftermarket base pads. Competition shooters often run Taran Tactical or similar extensions to add several rounds and speed reloads. It also accepts 33-round Glock stick mags.
Do I need a gunsmith to upgrade a Glock 34?
No, for most parts. Red dots (on MOS slides), triggers, sights (a sight pusher helps), barrels, magazines, extensions, lights, and holsters install at home with basic tools. Cutting a non-MOS slide for an optic is the one job worth a gunsmith, but the upgrades on this list are designed to be straightforward drop-in installs.
8,547+ Gun & Ammo Deals
Updated daily from 200+ top retailers. Filter by category, caliber, action type, and price.
Related Guides