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How to Replace Your Glock Barrel

If you judge by Instagram and YouTube alone, everyone and their dog is modifying their Glocks at home, but for some of us, those modifications can look a little daunting. That’s why this week, we’re going to take you through how exactly to do some of the most popular Glock mods.

Don’t be intimidated if you are not mechanically inclined.  You really can’t break anything.

First, the obvious.  When installing your replacement barrel in your Glock, take safety seriously.

1. Ensure there is no magazine in the gun and pull the slide to the rear to visually inspect the chamber.

2. Hey you! DO NOT simply rack the action and rely on the extractor to remove a cartridge from the chamber. I did that once with a .22 when I was 12 and shot my Dad’s suburban.  Not as cool as it sounds.

3. On that note, point the gun in a safe direction at all times, but especially when you dry fire it.

4. Once you have visually inspected the gun, make a final check that there is no ammunition in the area where you are working.


Ok…replacing a barrel is the easiest of all Glock mods out there. It can be done in less than a minute once you understand a few basic steps.

Step 1– Remove the magazine and clear the pistol. Finish by dry firing the pistol in a safe direction  The trigger must be to the rear for this process to work.

Step 2– Use one hand to withdraw the slide approximately 1/8thof an inch.  Not too much! If you pull the slide back enough to reset the trigger (about ½”), the slide will not come off.


Step 3– With your other hand, pinch the slide lock (take down) and simultaneously pull down hard on both sides and hold.

Step 4– Allow the entire slide assembly to come forward off the frame rails.

Step 5– Flip the slide assembly upside down.  Make note of how the recoil spring assembly nests against the bottom of the barrel.  Lift the recoil spring up and away from the barrel.  It is a captured spring and will not fly away.

Step 6– Lift the barrel out of the slide

Step 7– Lightly lubricate and install your new barrel in the slide


Step 8– Reinstall the guide rod ensuring the back of it nests into the notch on the bottom of the barrel.  You will have to slightly compress the spring with your thumb to accomplish this.


Step 9– Starting from the front of the frame, slide the slide assembly back onto the frame rails and rack the slide.  It will lock in place.  Rack and dry fire a few times to ensure function.



Why a Shadow Systems Barrel?

The main reason to replace a handgun barrel is to enhance accuracy.  Competent shooters will typically see a 50% increase in accuracy with a match grade barrel over a mass-produced stock barrel.  Shadow Systems match barrels for Glock pistols fit slightly tighter in a few key areas of the slide thus reducing changes in barrel position within the slide from shot to shot.  Each time the slide cycles, the barrel returns to a more consistent position relative to the sights.  This means shot to shot spread is reduced.

Shadow Systems barrels also use conventionally cut rifling versus Glock’s polygonal rifling. Despite the marketing around polygonal rifling, there is a reason you don’t ever see polygonal rifling in match barrels.  Conventional rifling deeply engages the projectile during its travel through the bore, fully imparting a consistent, stabilizing spin to the bullet. Conventional rifling is also is safe with unjacketed lead bullets for those who enjoy the benefits of this low-cost practice ammunition.

Meanwhile, Glock’s stock barrels should not be shot with unjacketed lead bullets.  The polygonal rifling can collect large amounts of lead from the bullet, gradually constricting the bore.  This can result in severe in a severe over-pressure situation and the firearm to explode.  You will find wide ranging opinions—some people shoot lead in Glocks without incident, some have had guns explode.  It seems the accumulation of lead in a stock Glock barrel is unpredictable, to say the least. Therefore, if you do shoot lead bullets, a conventionally rifled barrel like ours is recommended.

Lastly, top-of-the-line barrels like the Shadow Systems match grade barrels feature exterior machined flutes.  In addition to improved component weight and rigidity (modest, but real), the flutes give debris an escape path during cycling.  If your gun is filthy, or dirt and other debris enter the slide, flutes will generally allow more smooth cycling than a conventional barrel.

Shadow Systems barrels are available in premium Bronze Titanium Carbonitride (TiCN) and Black Diamond-Like Carbon (DLC) coatings.  Check out our website FAQ for information on these finishes.


Lastly, we are here for you to help you choose the best Glock mods!

If you give this a try and get stuck, we’d love to help.  Seriously.  Just call us at  469-458-6808.


Explore Shadow Systems Barrels.

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2 Replies to “How to Replace Your Glock Barrel”

  1. Kevin says:

    Can I put a G19 barrel into the MR920? I have a threaded barrel that can’t go where I am heading to next.

    1. Jessica Roe says:

      Yes, that barrel should fit fine. However I should note that we cannot guarantee the function of the pistol with non-Shadow parts.

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