https://news.ghostguns.com/2017/05/29/p320-compatible-80-insert-ghost-guns/

This is going to be game changing.  I just hope it isn't going to be rule changing as well.

I would be wanting a bunch of these if the price is right and a jig is available.  

::like::

interesting...

Cool...but until the aftermarket takes off at a full sprint with the P320 parts (I know people say it's going to, but I'll believe it when I see it) I'll sit back and watch.  The only reason the Poly80 Spectre was able to get off the ground is because of the overwhelming aftermarket support for Glocks.  That same support just doesn't exist for Sigs.

I can see that happening thought with the military picking it up and all the people who "what to shoot what I'm going to carry". May take a few years but unless this thing takes a dump after heavy use I think it'll happen.

You're playing in hypotheticals. I do see demand for the 320 going up, that much is already evident.  But the demand for the AFTERMARKET is what is going to make or break an 80% gun. Just because sales go up doesn't mean the aftermarket manufactures will jump on that train like a fat kid on cake. 

Yes there is the allure of the (and I fucking hate this term) "ghost gun" but that segment of the 80% crowd will buy the parts direct from sig. The problem is that segment is quite small in all reality. The vast majority of people in the 80% game either (1) like to tinker or (2) like something unique/built-not-bought. Virtually no one is in it to save money....espcially with the handguns and even still with ARs

I imagine it will come as a flat, and you'll have to bend & drill it.  Could be wrong.

Hmm, homebuilt Maxim 9 style integral pistol based on the P320 frame/grip...

@backbencher when your life settles back into some semblance of normalcy let me know if you want to collaborate on a modular FCU project.  I've got plans for prototype but haven't had any time since kiddo #2 was born.  

Lol, sure, but you're asking a Political Science grad, not an engineer.  

Wait'll I get back from the honeymoon.  I need to buy a vice, then I can fold things.  I already have very bad Dremeling skills, as shown by the scars on the Lyndon.

What platform were you thinking of?  AR, SIG 250...?

Whatever bro, I'm a Psych and Business grad.  Just played gun plumber for a few years when I had my own shop. Sample, you and I messed around with the fruity ghost stuff. 

Glock, because parts are cheap and available and Borris' Iron glock is vaporware.  The possibility of dropping this into other platforms (I.E. Semi tube guns) is intriguing to me.  Might also be able to make the non-existant "glock carbine" too.  Once the FCU is built and functions the sky is the limit...to include a potential bastard gun that uses glock components and another companies mags in a design it yourself grip module.  

I like the way you think! 

Looks promising

Anyone who wants to contribute and join in on the gangbang is more than welcome. 

If I can can figure it out it'll be an open source project with a free blueprint to DIY the flat and jig/molds

Given the amount of time Boris put into the Iron Glock, and still came up w/ a steel frame, we might find it more useful to hack the SIG 320 to use the ubiquitous Glock mag.  I'll grant there's nowhere near the aftermarket for the 320, but given its adoption by the Army, there will be.  It will take quite some time, however, for 320 mags to have the penetration in the market the imperfect Glock mag does.

If we hack the 320 frame for Glock mags, we might also be able to hack it for Glock slides - and then we can go nuts.  We'll be limited by the SIG grips to SIG mags, until we 3-D print, cast, whittle, or build grips out of Legos.

If we hack the 320 frame, by extension, we have very nearly hacked the discontinued 250 frame, which handled everything from .22" LR to .45" ACP, including .380".

Ruger also has a frame in their American pistol, which might be the easier hack.

I'm in, just let me know what you need

a case of mini rip-its or wild tiger and 10# of SPKs (sour patch kids)

Just kiddin'.  The biggest thing is if you guys can take a set of calipers to your frame rails and let me know how "thick" they are.  I need a larger sample size of measurements so I can determine what the tolerances are.  I've got plenty of Glocks so I'm good there, but I've only got 1 P320

FWIW If I can nail down the thickness of the FCU it's completely possible to then make a PDF template that you glue to the sheet metal (much like an AK flat) so you can drill the holes, cut the parts out that need to be cut, and then know exactly where to bend it.  I'll try to keep it cromagnen level and use 1/4" plate for the bending jig and at most you'll have to silver solder the pieces together.

So I can't speak for the Ruger American (apart from "I have no desire for a ruger american, even a roll your own") But the Fire Control Module for the P320 is not wide enough to accomodate the glock mag. Its just not big enough. The magazine will not sit high enough to present a round to the slide for chambering. This appears to be a hard and fast limitation.

That said, there's loads of other common, cheap, plentiful magazines out there that will fit. Beretta and M&P come to mind. I know it's not as ubiquitous as the Glock, but as fun as glock mags in a 320 would be, it's not going to work. Would much rather see an M&P magazine frame (potentially the next-best-thing to Glock mags) and I'm very interested in a Maxim9-esque frame project. (Beyond my ability, but cool nonetheless)

The modularity of the 320 is very exciting, it's disappointing Steyr didn't do more with their patent, we could have had this years ago. :( 

So - Glock mags won't fit inside a stock 320 frame - but we don't have to make a stock 320 frame.  I've also not seen pics of anyone trying to put a 9x19mm Glock mag into a .45" ACP 320 frame.

I keep forgetting about the Steyr - that's another option.  Not that there is, or is likely to be, any sort of aftermarket for the Steyr.

The easiest thing might be to adapt a 320 frame to take a different slide - Glock being preferential, of course, but would be amusing, for instance, to adapt the 250 frame, mag, & grip to a 1911 slide.  

The fact that there are multiple striker fired slides on the market, as well as multiple FCS frames & grips, really opens up some possibilities.  Glock slide, SIG trigger bits, on a Steyr grip?

Well when you say "frame" I assume you mean "Fire Control Module", then? The .45 320 Fire Control is the same width as the 9mm, glock mag is too wide for that. You're right, we wouldn't HAVE to make a 320 compatible fire control unit but...it'd be a lot more work to not, as then you'd be on the hook for design and implementation of smallparts. Not impossible, but now you're designing from the ground up using a 320 as inspiration. 

Given there aren't small parts on the market for the 320 anyway, other than a single trigger, I think we're on the hook for the small parts anyway.  Hence K1's intent to go w/ Glock parts, as there's a metric shit ton of em.

So - here's the issues:

Glock is the elephant in the room.  You can right now build a Glock using no Glock parts whatsoever, including an 80% Glock.  There are a dozen other guns on the market that take Glock mags.

The SIG 320 is the closest, easiest chance we have to easily make an 80% - or even 0% pistol frame, as the grip comes in one entire piece, even if it locks us into SIG mags.  But there's no small parts available other than a trigger, even if the gips, slides, & bbls are all available from SIG.  However, given the Army's adoption of the 320, we can expect aftermarket parts soon, and an increasing # of other guns that will take SIG 320 mags.  Not @ Glock levels, but parts and other guns will be available.

Our other options in making a simple frame are the Ruger American and the Steyr.  Steyr would be our last choice, given the total lack of aftermarket support; we can expect the Ruger American to lag behind the SIG 320 in the aftermarket due to their lack of military adoption.

So why not make a Glock miniature frame, as K1 proposes?

1)  Boris tried doing that, and ended up w/ a complete steel frame.  He's not stupid, as evidenced by his other 0% projects, so I'm not sure we'll be more successful than he was.  (We can take the Iron Glock design & modify it,, however)
2)  The Glock FCG is not designed to fit into a tiny frame like the SIG 320's FCG.
3)  The SIG 320's FCG IS designed to fit into a tiny frame, and we'll soon be able to piece it together.
4)  Glock magazines, while ubiquitous, are huge for caliber b/c of their plastic construction, and there's no grip for a separate frame designed to fit them, so we'd have to 3D print grips.  K1 suggests using different magazines, which will fix the issue.

If we design our own small parts, then we really could adapt to any striker fired slide we wished.  I agree w/ K1, there's a tremendous argument based on the aftermarket to go w/ Glock slides, Glock FCG, and Glock mags.  I just think the FCG is gonna be an issue.

So to try to clarify my intent....

Replicate the P320 FCU in a steel flat.  A template you print out is glued to the metal so you can drill holes, make cuts, ect.  Once all holes drilled and cuts made you'll bend the flat (and likely heat treat as well).  This is the "proof of concept" before jumping it off to a bigger project which is to make a glock FCU.  This FCU can be easily adapted into many other designs (I.E. semi sten, sterling, Sumoi, ect.).  You could even theoretically make your own handgun a la carte so to speak so long as compatibility between parts is there.  

Now speaking about the a la carte handgun.  The issues here are...

(1) sig small parts are practically unobtainable currently.  Saying "the aftermarket will catch up" is counting your eggs before they hatch.  Yeah they might, but they also might not because of patents and what not.  IANAL but that's how I see it.  The easiest work around is to use GLOCK parts because there is the aftermarket support to build a "not glock"

(2) P320 mags are stupid expensive, but looking at them next to my M9 and P228 mags they look similar.  I need to investigate to see if the angle they hold the rounds at is the same or not.  If they are, then you need to check to see if the slide will clear the feed lips or if they need to be modified/cut/adjusted/tuned.  Then the only thing stopping you from using those mags with the slide/FCU is the grip frame.  You will have to design the grip frame via 3D printer to make a positive.  Then cast a silicone mold so you can make your grip frame in the same method as the fruity ghost AR15 lowers.  

(3) if P250 frames (which I thought the P320 frames were compatible) and small parts were readily available I'd probably take a stab at throwing a 1911 slide on top of one.  A high cap polymer framed 1911 is one of my dream builds...but STI's cost too much and the RRA import (BUHL) are too expensive for my tastes.  Been wanting to fruity ghost a 1911 for a while now but time/family/work seem to fight for my attention so these projects fall off the burner quite frequently.  

ETA: Frame = Grip I use them interchangeably.  If I state FCU I mean FCU.  


One of the hardest parts about designing a semi-auto firearm are the magazines.  The easiest way to get around this when you're designing something new is to just re-use something already produced and build from that.  Saves a metric shit ton of R&D time.  Glock mags are easy, cheap and plentiful so they're a commonly looked at option.  For single stack mags 1911 mags tend to be the go to.  Other high cap/double stack mags to look at are Beretta mags since they're pretty cheap as surplus but not as cheap as Glocks.  

1 - True.  However, I would argue two things - aftermarket 320 parts are inevitable, and downloadable workable instructions to produce home-built 320 receivers from sheet steel will only accelerate that timeline.

2 -  3D-print the grip mold, not the grip.  If someone came up w/ a 320 grip that took Beretta 92 mags, it would save the Army a ton of money, and might bankrupt SIG.

3 - 250 2nd gen grips and mags are compatible w/ the 320 receiver.  Apparently, 250 bbls are not, killing my dream of a baby killing capacity 320 in .380".

ETA:  Shall we call the little metal part of the 250/320 that makes it work the receiver, the grip the grip, and the small parts the FCG that goes IN the receiver?  Might save a lot of confusion among noobs down the line.

Bro I've got a newborn in the house in addition to a high energy 3yr old and a wife who's still recovering....I'm not gonna remember terminology changes so I go with what comes to mind.  

Good call on the mold idea.  Might as well keep it KISS....if only I had a 3D printer.  Frankly the contract's already been signed and Big Green plus the rest of the DoD is going to go with the 320.  Eventually the M9 will be life cycled as well as all the parts/mags/ect from the supply system.  No sense in trying to make something like that to compete.  

In regards to the aftermarket.  Call me a pessimist.  You don't see a metric shit ton of parts for the M9 on the market.

The M9 doesn't really lend itself to being profitable for the aftermarket like the glock does, and the Sig can.

ok, I'm tracking, although small parts are available for the P320, i acknowledge they're stupid expensive with limited availability at the minute. However, out of 15 parts in the FCU:

4 of them are shipping with every grip frame at the moment: (1, 6, 7, 8)
5 are pins (3,4,10,12,14)
1 is widely available (11)
1 is the component we're discussing (5)

That leaves the infamous trigger spring, the trigger bar (if you can make #5 you can make the trigger bar) the takedown safety, and the sear assembly. All currently available for a little over 100 bucks from numrich. If 80%'s take off, I think you'd begin to see aftermarket parts for a lot of those (especially the trigger bar, since that would potentially benefit from some hi-po coating/slick redesign).

I guess my point is that with the Military adoption, the P320 isn't going anywhere, and unlike the M9, the P320 was already a pretty successful pistol on the commercial market before military adoption...the 80% P320 receiver seems a lot lower risk than the Glock 80's, which are quite popular was well, despite a similar lack of availibility for small parts AND glock not selling slide assemblies separately (unlike Sig).

 I mean whatever, I'm just happy to see the concept of "at-home manufacturing" of firearms taking off. 

Well, we don't need the takedown safety lever - nice to have, but not necessary, and we'd have to make our own trigger bar anyway to squeeze Glock mags in.

Foldable sheet metal for the receiver, tool steel or pre-hardened steel for the trigger bar and possibly the ejector.  If we make the receiver stupid easy to make, then use soft, easily foldable steel & just make another one when it starts peening or whatever.

(Steel terms at Aggie liberals arts major level, not exact specifications)

I saw there is a grabcad drawing out in the wild somewhere, just wondering if there was a P320 cad file out there?

I wouldn't be surprised if there is a file floating around out there, or if not someone is probably working on one. There was a post a while back about a billet FCU, so they had some sort of drawing to go off of. 

ill eventually get around to pulling the FCU out of my 320 for measurements and making a rough paper template. 

Someone should write the ATF a letter.

fuck no

All the parts are avalible, just expensive.

https://www.gunpartscorp.com/Manufacturers/SigarmsSigSauer-33490/AutoPistols-41939/P320-43399.htm?results=All

My plan is to buy a used 320, strip the parts and make my ghost P320.

Then I can always sell the leftover FCG housing to recover my cost.

I think once the P320 becomes more widespread more parts/aftermarket parts will be available.

I'm no expert on these sorts of things, but how easy is it to bend that thickness of metal with enough precision for the gun to work right?  Would it be better to have it bent on the proper tool, and sell it just needing drilling and parts?  I can drill holes using a jig in my garage on a $60 drill press.  

Take a look at AK flat builds. The bends are relatively easy to make. The slide rails will be oversized so you can file to fit. 

Speaking of this project. I need the slide rail dimensions from multiple guns. If you guys can post them up I would appreciate it. 

From behind the gun I need the front and rear rail thickness (up and down), length (muzzle to rear), and and width (left to right). 

http://www.printedfirearm.com/3d-printed-sig-p250-frame/

http://www.printedfirearm.com/3d-printed-sig-p250-frame

ETA:  And this is where confusion begins.  To be clear - this is the grip, not the receiver.

Jesus. And I thought I was being ambitious just trying to make a grip that could take S&W mags.

If you have a M&P frame cad file you could combine the two and it would possibly work. You have to make sure the feed lips have the correct presentation angle and the slide won't bind on the feed lips

Soooo here's something interesting.  I think can make this 80% compatible with all offered calibers. 

If we can sort out other compatible mags then non standard calibers may be an option. I would need to check to see if the chambers on the barrels could be reamed a little deeper. 

That's comparatively easy.  Make it take Beretta 92 mags and make a fortune selling it to the Army - and bankrupt SIG in the process.

I think aftermarket support is going to explode soon, simply because Sig is too busy filling orders for the military to focus on civilian sales. Combine with the exploding popularity of the gun and you have a market void that any manufacturer wouod be insane not to try to exploit.

High demand + low supply = $$$

Hell I'm in.  Might just be the reason I needed to buy a 320.

Sub'd !

@AFCarbon15 I'll let you know.  I might need some assistance with making the press jig for the flats.  I don't have a mill so I'm relegated to shaping metal by hand and silver soldering it together for added thickness at this point.

Kinda defeats the point of an open source build to contact a vendor who'll make and sell the product. 

Ideally both the flats and the jig. I'm going to try to make the jig out of a piece of 1/4" plate you can get from any hardware/farm store. Bending into a U shape is fairly easy. It's that indent on the sides that is a bit tougher.

if it isn't feasible with a DIY jig and instructions then I'll think about approaching Kvar or some other manufacturer. Maybe I might tackle it myself since I doubt that interest and buyers are going to be equivalent. 

looks like SIG made the FCU out of 14GA stainless based on the thickness of it (0.078").  The idea to use this for any other sort of magazine means that mag cannot exceeded (0.75") where it fits between the FCU and the "transfer bar" for the trigger (I'll fix this nomenclature later).  The max width for the feed lips is around (0.6").  Making a scaleable PDF for a steel flat will not be a problem.  Stamping this however, might be.  I'll try a few different ideas using an arbor press and jig, using a jig and a shop press (12 ton), and if worst comes to worst making a "flat spot" type FCU out of carbon steel (the one option all of us overlooked, all holes could be drilled just setup, weld, and go).

From my understanding the FCU's are different between 45 and 9.  What that difference is I'm not quite sure.  There's not a whole hell of a lot of room they can alter the FCU itself.  It may be that just the mag disconect safety is what keeps the 45 from going into the 9 FCU.  If that's the case ditch the mag safety and the problem's solved.

FYI all my frame rails measured 0.0735" at the lowest and 0.075" at the highest.  Average of 0.07425" 

<ETA> There is one other alternative option for the FCU.  I can provide instructions for how to build a easy/cheap/quick sheet metal bending brake.  That way you only need to press the mag well bends into the flat.  I MIIIIGHT be able to modify the brake a bit to make all but the "bend overs" (frame rails, ejector, and all other tabs bent over that aren't the FCU body).  Those would have to probably be done with a filler panel, a bench vise, a hammer, and a liberal application of M.A.N. to it.

I need to try building the brake before I even contemplate anything further with the FCU.