(Sometimes things just don’t work right)
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P320 80% Build Adventure
So you are thinking about building a Sig P320 80% pistol. Awesome, you have come to the right place. I am going to walk you through the adventures that I had when making the Sig P320 80% video.
I am not big on the unboxing videos and quite frankly, had no intention of writing this article. However, I did run into some minor issues early on this build which prompted me to write this.
Because there was no intention of writing this article, I missed the opportunity to get pictures of the jig when I took it out of the box.
Before I go any further, I want you to understand that this is an unbiased article. There was no vendor solicitation and everything here was purchased at full cost. These vendors have no idea that this article is even being written and I did not tell them that I was an FFL holder (not that makes a whole lot of difference in the 80% world).
For full disclaimer, I am a Type 1 FFL which allows me to sell firearms and do gunsmithing activities. It does not allow me to manufacture a firearm for resale. All 80% firearms that I build are for personal use only and are not for sale. Some fixtures, tools and/or jigs that I may talk about or show in a video series may be owned personally and not by my company (Eagle Eye Shooters Supply).
I do not advocate building any firearm or suppressor to bypass (break) Federal, State or Local laws or ordinances.
Since the video series went live, Jordan from JSD Supply asked if I would like to become an affiliate which I accepted. Links to JSD Supplies’ parts and tools on this website are now affiliate links. If you like the work that we did on the video series, please consider clicking on our affiliate links when purchasing parts or tools.
There is no doubt that it is much cheaper to buy an off the shelf firearm than build one and 80% builds can be more expensive than other custom built guns. It is important to remember that 80% builds are typically done for the pride of accomplishment, as well as, having a totally custom gun that meets the specs that the builder may require. When you start getting into highly specialized guns, the 80% route may eventually become cost-effective the more you build.
I am sure you are reading this article wondering how much this build cost. To address your curiosity, I have posted a table listing the costs of this build. Of course, there are some tools that I already own that are not on that table. If you would like to know all of the tools that I used, please visit the article Tools used in the P320 80% Videos that lists the tools used and what step I used them in.
If you do an internet search on P320 80% you will find multiple sites that sell the frame and jig kit from JSD Supply. I decided to purchase the frame and jig kit directly from JSD Supply because of a memorial day coupon for free shipping. The price on their site is the same as any other site but with free shipping, I saved a few dollars. Actually, I saved about $27 since the code was for free shipping no matter what service I chose… so, of course, I chose next day. My order from JSD Supply included the P320 80% Frame and Jig. I did not order the lower parts kit as it was sold out so I had to do some searching for those parts. But we will talk about that later in the article.
Jig Issue #1
There are 4 screws that hold the jig together. I removed the 1st screw with no issue but when it came to the 2nd, I ran into issue #1. What I can surmise is that someone torqued the screw so tight that I stripped the head when trying to remove it. I decided to continue and bypass this screw and move forward. I became really worried when I got to the 3rd screw and the same thing happened. Moving on I easily removed the 4th screw just as the 1st.
To be honest, I was getting a little frustrated and was having second thoughts about doing this video series. I wrote an email into JSD Supply at 7:43 PM letting them know about the issue. Now that I had the release of frustration I decided to move forward with another video series and revisit the P320 80% later. Little did I know I was going to end up doing both series at the same time.
To my surprise, I got an answer from JSD Supply 3 minutes later. And after a quick dialog, they offered to replace the jig when the next batch was ready in 4 days. I told them I was going to reattempt removing the screws in the morning using an EZ out and may not have to take them up on the offer.
The next day, I tried once again and broke 2 magnetic tip #2 Phillips bits, but finally, the screws were out without having to use the EZ out. Fortunately, the tips I broke have a lifetime warranty and a quick phone call to Brownells had them replaced.
Jig Issue #2
Now with that disaster avoided, I can move forward, right? That’s when I ran into another issue.
I started laying out the drill bits that came with the jig and making sure I understood where everything fit when drilling. I found that the 9mm and #40 drill bits are too large for the holes in the Jig. At 9:38 am off went another email to JSD Supply telling them I got the screws taken care of and asking “It looks like the 9mm and #40 drill bits are too large for the holes in the jig. All of the other bits fit their respective hole. Is this normal?”
Once again, the stress release of sending an email was allowing me to move on with my day. 2 minutes later I heard the ding of an email message on my computer. I checked my email to find a reply from JSD Supply stating “Yep sometimes the variance in machining and drill bits overlap. You will be good.” I am beginning to think that they are on the other side of the computer just waiting for someone to email them no matter what time of the day it is.
With my confidence restored that no matter what happens on this project, JSD Supply will be there to help me.
Now it was time to find my source for the lower parts kit.
Lower Parts Kit
After you have your Jig and 80% frame you need the “guts” or what is commonly known as the lower parts kit. JSD Supply was out of stock when I ordered the frame and jig (so was Ghost Guns and every other place I ran across in my searches). This left me with a dilemma, I could either put the entire project on hold or split the project into 2 videos and continue moving forward in steps.
Desperate to continue, I tried to source the parts individually on Brownells and Numrich and quickly found I couldn’t get all the parts I needed yet alone find all of the upgraded parts for the drop fire issue.
In my searches, I saw a posting on Calguns about building 80% 320s and people complaining about getting parts. In those postings, a person was saying that they can source parts. I checked out their website (ABprototype.com) and sent them a message at 3:59 pm and to my surprise, I had a response at 4:19 pm.
After a few emails with Alex over at AB Prototype, he able to get me a refurbished lower parts kit with the upgraded parts. In our email chains, I learned a little about why some of these kits may be so expensive other than the P320 is a relatively new gun on the market and parts are still scarce. He is pulling the Lower Parts out of complete pistols and left the rest of the gun to try to sell.
If you are having problems finding parts, drop by ABprototype.com and see what Alex can do for you. When you are ready to install them, visit our P320 80% Parts Kit Install Video to learn how to install them into the FCU after you have finished your frame.
Understanding Drill Speeds
To Build the P320 frame you will need to use 7 different drill bits (my kit came with 7 HSS drill bits) and a drill press.
One thing to understand about Drill Press’, you need to operate them at different speeds for the different drill sizes. So you will need to do a little bit of math to select the correct speed for each drill bit. I used this formula to figure out what speed to use on my press, (SFM X 4) / Drill Bit Size in Inches
I did the math already for you and the following table will help you with selecting the speed of the drill. Thanks to switchpod on the Full30 Forum for helping me understand how to come up with the correct speeds. These are calculated for HSS drill bits (the cheapest drill bits available). If you have a different drill bit type (Cobalt, TIN, etc.) you will probably need a different formula.
|Drill Size||Drill Size in Inches||SFM OF Stainless Steel||RPM of Drill Press|
Now that we know the speed of our bits we can set up our drill press for the first hole. Chances are that your drill press will not have the speeds listed. You will need to run your drill press at the closest speed listed and when in doubt, go with a lower RPM. For instance, the #40 bit should run at 2,041 RPM and my press has the closest speeds of 1,850 RPM and 2,260 RPM. This means I will use 1,850 RPM and drill slower (apply less pressure and taking longer to drill).
The important thing to remember is the faster a bit turns, the hotter it gets. Also, heat dulls bits quickly. Generally, it’s a good idea to drill through metal using a slower speed. Hard metals like steel, as well as, larger drill bits require slower speeds than soft material like wood and smaller bits.
To allow my drill bits to last even longer, I used cutting oil when drilling since it reduces heat buildup and friction. Also, I like to lift my drill bit to clear out the chips, cool the bit and apply more cutting oil. When drilling this frame you are not really drilling deep enough to do this however, I tend to follow this practice anyway.
What I would do differently
After test firing, I found a couple of things that I would do differently in the beginning.
First, I noticed a good amount of wear on the frame where the trigger bar was rubbing. I would polish the frame a bit more in this area.
Second, I would round off the edges of the frame. I found that the frame rubbed on the slide.
Other than these two items, there are no other things that I would do differently. The build went well and was fairly easy to do. Not to mention, the gun has proven to be reliable so far.
This was a fun build to do and I really enjoyed doing it. Building a P320 is pretty easy to do and can be completed in a weekend. If you are considering to go down the road of doing an 80% firearm, I would say that this is a good one to do to build your confidence.
Some people have asked me if this build can be done with a hand drill instead of a drill press. I would say you probably could but would not recommend it. If JSD built the jig with some hardened steel inserts I would say you might get away with a hand drill.
If you like the work we do here, please consider supporting us for free by doing your online shopping using our affiliate links and banners on this site. You can also support us by donating on Patreon.
As you can see in the following table, this build did cost a significant amount of money and your support allows us to keep producing content.
|P320 Referb LPK||209.00||ABprototype.com|
|Xchange Kit||$0.00||Had one for my existing P320|
Sig E2 Grip Replacement
There has been a lot of debate on doing a Sig E2 grip replacement with a regular 2-piece grip and vice versa. In this article, we will explore the Sig E2 Grip Replacement question and let you know what works.
E2 = Ergonomics Squared
Sig Sauer released the E2 line of their “Classic Pistols” to change the ergonomics of the gun to make it more adaptable to a wider range of shooters. However, the E2 grips strengths for some shooters are also its weakness for others.
The E2 Grips are slimmer, have no screws and have more texture so that the shooter has a firmer grip in various conditions.
Shooters with smaller hands seem to like the E2 grips as they can wrap their hands around the frame better which in turn gives them better trigger finger placement. However, some larger handed shooters may find that the E2 grip is a little on the smaller side for them. I personally have larger hands and have no problem with the thinner grip size and quite frankly like how the pistol feels in my hand.
I find the most annoying part of the E2 grip is the lack of grip screws. To remove E2 grips you need to use a special grip tool that comes with your pistol. To remove the grips you lock your slide to the rear and insert the tool into the mag well. From there you twist it to spread the grips from the frame and remove them from the rear (see our E2 Grip Removal and Install Video). This is good in theory, however, I find that the E2 grip tool does not spread the grips enough to remove them from the frame. Also, maneuvering the grip around the Decocker and Trigger Spring during removal and install is awkward. I use zip ties as wedges to spread the grips a little more to remove them and avoid pulling off the Decocker and Trigger spring during removal or install.
That being said, I love the texture of the E2 grips. I feel that I have a good purchase on the pistol. I do find concealed carry to be a little challenging with the rougher texture as It will rub my skin raw. However, that is nothing that an undershirt hasn’t solved for this and other carry pistols that I have.
Can I change my standard 2-piece grip to an E2 grip?
Yes, you can change your standard 2-piece grip on the P220 (DA/SA), P226 (DA/SA) as well as the P229 (DA/SA and DAK). However, it is not quite a direct replacement. Sig sells an upgrade kit for about $70 on their website to do this. Shopping around on the Internet I have seen this kit selling for as low as $55. This kit comes with the E2 grip tool, Hammer Seat, Hammer Strut and on DA/SA kits, a new decocking lever.
I have not figured out why you would get a new decocking lever in the kit as the two pistols that I used for the research on this article had no problems with clearance in the Decocker or its function regardless of which grip was on either pistol. This leads me to believe that there may be a difference in decocking lever between the old-style and the new-style as well as the E2 pistols.
The Hammer Strut and Seat were redesigned in 1999 to what is commonly known as the “New-Style”. The old-style 4 piece hammer strut assembly (see my old-style hammer strut disassembly and reassembly video) was replaced with this new-style 3 piece assembly. The replacement essentially changed out metal seat with a plastic one eliminating a pin to keep the assembly together. To accommodate the new seat, Sig also redesigned the spring. The new-style is much easier to maintain than the old-style as you can see in our Sig Classic Disassembly and Reassembly videos. However, with the introduction of the E2, Sig once again redesigned the Hammer Strut and Seat for use with the new grip style.
I highly recommend that you purchase the E2 upgrade kit to switch out the grip. You can put an E2 grip onto a pistol with the “New-Style” of hammer strut and seat. However, there is some rubbing that happens on the hammer strut and spring and you will notice that the grips move slightly when that rubbing happens. I did not have access to a pistol with the old-style hammer strut assembly to try out the E2 grip with it. However, I would expect it to rub as well.
Can I change my E2 grip to a standard 2-piece grip?
Yes, you can change your E2 grip to a standard 2-piece grip as a direct replacement. The E2 Hammer strut has plenty of clearance in the 2-piece grip not to mention that the frames are still threaded to accept grip screws. If you have an E2 Hammer Strut and Seat installed on your pistol you can easily switch from an E2 Grip and standard 2-piece grips.
I believe that Sig has done a great job keeping their Classic pistol line up to date with shooters needs. If you need a thinner grip or like the feel of the E2 grips you can switch out to the new grips easily for a reasonable cost. If you have the new grips and want to change out to a more traditional grip, it is a direct replacement of the grip.
P320 80% Range Testing Video
Our P320 80% Range Testing Video will show you the first shots of the build as well as some follow up work we completed.
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For the tools that we used on the Sig P320 videos visit http://trb.fyi/tools-used-in-the-p320-disassembly-and-reassembly-videos and visit our troubleshooting guides at http://trb.fyi/troubleshooting/ while you are at our page.
First Shots – 0:40
Load Three and Test Fire – 1:05
Load More and Test Fire – 1:15
Change Caliber to .40 and Test Fire – 1:46
Post Firing Inspection of the FCU – 2:12
Cleaning sharp edges and polishing the FCU – 4:07