Gun Cleaning How to Videos

Glock 21

Glock 21


A step by step video on how to clean and disassemble your Glock 21 Gen4 handgun.


Recommended Gun Cleaning Supplies for Your Gun Cleaning Kit


Step One

This instruction will work on other Glock models as well, but we’re using the Glock 21 here as an example.


Let’s go ahead and first make sure that the magazine is removed and that your firearm is unloaded. 

How to unload Glock 21 pistol


Step Two

Now that we are sure the gun is cleared, release the slide, point the gun in a safe direction and pull the trigger.

Clearing a Glock 21 handgun


Step Three

Wrap your hand around the rear of the firearm like you see us doing here and pull back on the slide.

How to remove slide Glock 21

You don’t need it to go far back, just a little will do.


Now with your other hand pull down the takedown lever.

Glock 21 takedown lever


Step Four

You can release and push the slide forward.

 remove slide Glock 21


Step Five

Pull out the recoil spring.

 Glock 21 recoil spring

Then the barrel.

how to remove barrel Glock

Step Six

Now we’re going to grab a firearm parts tray. You’ll want to use something to contain the parts and allow them to soak in some CLP.


Place the recoil spring, barrel and slide into your parts tray.

 gun parts tray


Step Seven

Now grab your CLP and spray down all the parts in your tray. CLP is essentially a solvent for gun cleaning as well as a gun lubricant. It's a must have for your gun cleaning supplies.


Be sure to give a few squirts down the bore.

 solvent for gun cleaning

Everything else gets a good soaking as the CLP is going to do the heavy lifting for you when it comes to cleaning your handgun.


Step Eight

Now let’s pull out the rest of our gun cleaning supplies.


You’ll want a durable cleaning cloth that won’t tear on the sharp edges of your gun.

 gun cleaning cloth

Next you’ll want to grab a .45 cal bore cleaning kit for buffing out your Glock 21’s bore. A bore cleaning kit is similar to a bore snake, but it gives you a full bronze brush instead of a few integrated bristles in the buffing rope.

 bore snake for .45 cal

You’ll want a set of gun cleaning brush and picks to help scrub the carbon and whatever gunk that might be attached to your Glock.

 gun cleaning brush

Some firearm grease will be handy if you’re really putting the rounds through your gun.


Lastly you’ll want to get a hold of some long stemmed gun cleaning swabs.

 cotton gun cleaning swabs


Step Nine

Now we’re going to give all the parts that have been soaking in parts tray a scrubbing with a nylon gun cleaning brush.


We’re concentrating on the barrel first. Use the brush to break up any carbon on its exterior. Get in and work on the lug as well.

 how to clean barrel of Glock 21

After that, the recoil spring could use a light brushing.

 how to clean recoil spring Glock 21

Then you’ll spend the most time on the slide. Get in and brush down the rails. If you have a small end on your nylon brush, this is a great spot to use it.

 how to clean slide Glock 21

You’ll want to give the breech face a good scrubbing as well. 


Concentrate some effort on the extractor. It’s this little part that we’re pointing to here.

 Glock 21 extractor

This is a crucial part of your firearm that you want to keep clean. 


When you’re done with the interior, give the exterior a scrub down as well.


The interior of the frame could use a cleaning while we’re at it as well. Hit the rails and trigger group. A little work on the magazine well wouldn’t hurt either.

 how to clean frame Glock 21


Step Ten

Next we’ll grab a hold of our gun cleaning swabs and get to those areas that is going to be tough to reach with our gun cleaning cloth.


This will include certain areas of the barrel’s lug.


Then get to work on the slide. The pointed end of our gun cleaning swabs works really well for getting in there. 

how to clean slide rails Glock 21

Take your time and pay attention. Grit left behind will increase the wear and tear on your firearm so make sure to get everything out of there.


After that get clean up the frame. Hit the rails and anywhere else that looks like it has carbon on it.


Step Eleven

Finally we’ll pull a .45 caliber bore cleaning kit through the bore. You could pull the kit through while the firearm is assembled, but since it’s already broken down, we’ll do it like this.


Be sure to send it through the breech end of the barrel and pull it through towards the muzzle.

 handgun bore snake

If the kit is tight, good, you want it to be. A tight fit ensures a solid cleaning.


One pull through usually has the bore looking like glass.

 clean gun bore


Step Twelve

Now everything gets a wipe down with your gun cleaning cloth. Get all the surfaces on the exterior and interior.


As you clean off the parts from the parts tray, set them aside on your gun mat for reassembly.


Get to work on the slide next. We won’t bore you with showing you each and every surface being cleaned. You get the picture.

gun cleaning cloth

After that wipe down the frame. You can send your gun cleaning cloth through the magazine well to clean that up and make sure there isn’t excess CLP in there.


Step Thirteen

Now we’ll want to give all metal parts a light spritz of CLP to properly lubricate it. 


Get the slide, frame and barrel. 

 lubricating a Glock 21

A little on the recoil spring will help prevent any rust at could occur.


Step Fourteen (optional)

CLP in most cases works perfect for lubrication. But if you blow through ammo and don’t clean your gun as often as you should, a little bit of firearm grease might be necessary.


Apply a little bit to the lug and barrel. You can disperse it with a gun cleaning swab.

 properly lubricating Glock 21


Step Fifteen

Then place the barrel in the slide.

 replace barrel Glock 21


Step Sixteen

Hit the rails in the slide with a little bit of grease as well.


We’ll now insert the recoil spring assembly.

 replace recoil spring Glock 21


Step Seventeen

After that you can push the slide back onto the frame.

 reassemble slide Glock 21

Rack it a few times to make sure everything is smooth and buttery.

 how to clean and lubricate Glock 21

And there you have it, a cleaned and lubricated Glock 21. 


Sage and Braker, Crafted at the highest caliber.








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