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Why You Need To Make Your Own P320

The SIG P320 pistol is an extremely modular platform, much like the AR15 is for rifles, that allows you to pick your individualized components to fit the pistol to your needs and wants. 

Freedom On

Making your own pistol is, for now, still legal to do and you should!  Know the laws in your locality and make sure you follow them while also working to make it legal for everyone through the legal process.

The piece of metal you start with and jig

The process of jigging, drilling, cutting, and bending can be intimidating!  It does not really need to be though with the resources at your fingertips via the interwebs of technology.

Some pointers that I learned the hard way might make this a little easier though so take some notes and do not repeat my mistakes.  You do not need high-end tools and you do not need special skills sets or training. 

Start with the Basic Tools, your Components, and your Patience

Use a drill press and not a hand drill.  Yes, you probably can be successful with a hand drill, but I would not recommend it. 

Turn the drill press RPM’s down to about 1,500 RPM’s and use a high-quality cutting oil and use plenty of that oil.  Wear your safety glasses while you are working on this!

Leave the inner portion of your jig (“hammer block”) in place while drilling out the holes so you do not bend the walls of the FCU inward.  Let the drill bit pull through and do not push super hard trying to force it in like an angry gorilla (referring to myself).

Purchase your P320 in the grip module and slide configuration that you desire.  Full-size, carry-size, compact-size, or subcompact-size

Don’t Stress About Finding the Needed Parts

Get the parts at Fuzzy Bunny Movie Guns (FBMGUSA).

Solution Found! FBMGUSA.COM has the parts you’ve been searching for!

Watch the video from JDS Supply (or whatever supplier you found for the FCU, a few times with your components in front of you and learn how to drill it, bend it, and cut it out.  Here is a good video for you:

Once you have it all cut, bent, and drilled take your FCU and Fuzzy Bunny Movie Guns SIG P320 Lower Parts Kit and lay it all out.  Watch the video of how to assemble it all a few times with the components in front of you.  Here is the video for you:

The slide can be purchased as an assembled item or stripped.  If you choose the stripped slide, you are going to need to find the parts to finish it.  I have good news for you on finding these parts for your build, they can also be found at Fuzzy Bunny Movie Guns under the category of P320 Slide Parts Kit. 

FBMGUSA.COM also has the slide parts you’ll want!

The P320 Slide Parts Kit will include the Slide cap in black, Striker Assembly, Extractor, Extractor Spring, Extractor Spring Pin, and Extractor Guide Pin. Here’s the video of how to assemble these parts here:

Again, you’re going to need a 80% FCU, a grip module, FCU Lower Parts Kit, Slide Parts Kit, Slide, Barrel, and some magazines. 

Have Fun and Have Everything Grouped Up and Ready to Go

The FCU is the firearm once it is completed.  Follow Federal Law and your states law once you complete the FCU. 

Why buy a stock gun, strip parts, and build it the way you want? Just build the gun you want from the get-go and find the parts you need at FBMGUSA.COM

In review, you are going to need to use a drill press, have a good mallet, an armorer’s block like that from Real Avid, a vice, and some quality cutting oil. 

Not all P320 magazines are the same!  Make sure you pick up the right ones for your grip module.

Who Should Build Their Own?

If you have built a P80 and you want a new challenge, try one of these out.  They’re a little more work than a Polymer 80 (G19 build) but not near as much work as a 1911 80% build. 

If you have not built a P80 before and don’t know if you can do this, you can.  Follow the instructions, watch the videos, be patient, and you will be successful.

I love my P320 build.  I’ve always been a Glock guy and was slow to come around to the P320 platform but I’m loving the modularity and the ability to make this pistol my own.  I’m hoping to find myself a “gas pedal” take down lever for my build next.


The cost might be more than buying a stock P320.  Were you planning to leave your P320 alone and run it stock?  Then maybe this style of build isn’t for you but it sure is for me.  I can’t leave well enough alone and need to personalize. 

I like building my own things but more importantly, I never leave the gun alone and always customize them to what I want.  If I’m building it from parts, I don’t end up with a bunch of spare parts that I’ve removed and replaced with aftermarket!  That will save you money if you are in that category.

Once of the frustrations for the market has been parts availability to finish out the fire control unit.  I found a solution to that with Fuzzy Bunny Movie Guns!

Fuzzy Bunny Movie Guns has an upgraded P320 FCU (Fire Control Unit) parts package.  They have slick coatings for optimum lubrication and will leave you with a precise upgraded trigger.  The FCU kit is compatible with any upgraded Sig P320 slide in 9mm, .40 S&W, and .357 SIG.  The kit includes an upgraded Flat Trigger, Sear Housing, Sear, Safety Lever, Upgraded Trigger Bar, Takedown Safety Lever, Takedown Lever with O-Ring, a Mechanical Disconnector, Trigger Bar Spring, Sear Spring (x2), Takedown Safety Lever Spring, Sear Housing Pin, Trigger Bar Stop Pin, Sear Pin, Slide Catch Lever Pin, Safety Lever Pivot Pin, and a Slide Catch Lever Kit.

Now all those little parts can seem very intimidating to assemble but, in this day and age of online do-it-yourself videos, I’m confident that with any degree of mechanical aptitude and a solid internet connection you could assemble this thing.  If you are clumsy, do the install from inside the confines of a clear plastic bag so you don’t lose parts!

Freedom on

If you are ready to make the jump and build your own, let me save you some cash by checking out with coupon code “zck3vcf3” when you check out from Fuzzy Bunny Movie Guns!

About the Author /

Heath has been a law enforcement officer in the Great Pacific Northwest since 1993 and trains as a pistol and rifle instructor for both law enforcement and civilians. He also serves as an advanced armorer on pistols and rifles. If you're looking for training or would like to contact him, he can be reached at

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