80% FCG in the works - Page 2

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[ARCHIVED THREAD] - 80% FCG in the works (Page 2 of 2)

Posted: 6/9/2017 11:03:55 AM EDT

[#1]

In another 320 thread, someone confirmed the 9x19mm slide would fit on a .45" ACP frame; apparently you then had to pull the trigger to take it back down, hence SIG is not selling that combo. There is less restriction in the .45" ACP magwell, and I've not been able to get a .45" 320 owner to confirm that Glock mags don't fit.

Posted: 6/9/2017 12:03:20 PM EDT

[#2]

Quote History

Quoted:
In another 320 thread, someone confirmed the 9x19mm slide would fit on a .45" ACP frame; apparently you then had to pull the trigger to take it back down, hence SIG is not selling that combo. There is less restriction in the .45" ACP magwell, and I've not been able to get a .45" 320 owner to confirm that Glock mags don't fit.

View Quote

In pretty sure I read that the 45ACP FCU will drop into a 9mm grip/frame/plastic thing you hold onto. Looking at the dimensions I could believe it might be the same FCU only a different mag disconnect safety and grip/frame/plastic thing you hold onto.

Posted: 6/9/2017 6:18:36 PM EDT

[#3]

I picked up some of the 1/8" angle and flat metal I need to make the brake. Now I just need to cut it to the correct length and do a mock up of the design to see if it'll work for bending a FCU.

I'll make a test FCU out of some 16GA steel I have sitting around. Lowes doesn't carry anything thicker so I'll have to order some 14GA once the proof of concept has been completed.

Posted: 6/10/2017 8:35:24 AM EDT

[#4]

@backbencher

GSL posted pics of his FCUs. Looks like I was right. The FCU itself is the same. The takedown lever safety however is different.

The gun SHOULD function without that installed. It would however require dry firing the gun IOT to disassemble. If that's the case it would allow for a slightly wider mag to be utilized. I'll take my calipers to a few different mags to see what might work.

Posted: 6/10/2017 8:50:35 AM EDT

[#5]

Yeah, that's what I heard about the dry firing. If we're building our own, that's something that can be left out altogether.

Posted: 6/11/2017 11:29:30 AM EDT

[#6]

Sooo in regards to using other companies mags....we might be boned unless we redesign a good bit. Take a look at these pics.

Attached File

Attached File

First pic compares a P320, M9, and Glock mag side by side. The Second is a more detailed pic of the glock mag vs P320 mag (it's way too wide). The third pic is a side by side of the P320 and P228 mag.

The tape angle towards the top of the mag starts a LOT lower than all the other double stacks I have (didn't bother checking against H&K mags because they're stupid expensive too). I don't own an CZs, M&Ps, or other common double stacks to compare it against.

Posted: 6/15/2017 9:56:11 AM EDT

[#7]

I should have a sheet metal brake done this weekend. This one will just be a straight brake, and not the one that will be needed for the FCU project. I'll be making another one specific for this project. I have an idea of how it'll work but I need to make a regular brake first IOT figure out what needs to be modded for this project.

Posted: 6/20/2017 12:26:28 AM EDT

[#8]

I got nothing done on this project this weekend....but I did finish building another P228 from an 80% frame

Posted: 6/20/2017 1:03:15 AM EDT

[#9]

Sweet! Where are you getting the frames?

Since we're making our own grip/magwell - what if we put the slide lock on the outside of the frame? Would that give us more room for mags?

Posted: 6/20/2017 1:08:26 PM EDT

[#10]

Quote History

Quoted:
Sweet! Where are you getting the frames?

Since we're making our own grip/magwell - what if we put the slide lock on the outside of the frame? Would that give us more room for mags?

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Matrix precision

Attached File

As far far as the slide lock. Then that is one more part we would have to fabricate. Ideally I would like to stick with easily attainable commercial parts. and as I recall that won't matter much in terms of making more room.

Posted: 6/20/2017 1:27:29 PM EDT

[#11]

Quote History

Quoted: Matrix precision

https://www.AR15.Com/media/mediaFiles/114426/IMG-4838-234932.JPG

As far far as the slide lock. Then that is one more part we would have to fabricate. Ideally I would like to stick with easily attainable commercial parts. and as I recall that won't matter much in terms of making more room.

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Very nice. Do those take original 228 magazines, or the new M-11A1 mags?

In this pic, it kinda looks like the LRBHO levers take up a measurable amount of space in the magwell:

Attached File

Posted: 6/20/2017 1:47:47 PM EDT

[#12]

Quote History

Quoted:

Very nice. Do those take original 228 magazines, or the new M-11A1 mags?

In this pic, it kinda looks like the LRBHO levers take up a measurable amount of space in the magwell:

http://www.ar15.com/media/mediaFiles/41996/DSCN6907-233033.jpg

View Quote

Original 228/229 13rd mags not the newer 229-1

At the point where the slide stop levers are, high up in the FCU, it almost doesn't matter. The issue is on the other end of the FCU. Look back at the pics of the mags, notice where the taper starts. The P320 mags have the taper start really far down, this is so it can fit into the FCU. That means IOT fit different mags into the FCU you will for sure need to lose the take down lever safety as well as possibly re-engineer the FCU a bit. Obviously this is a "for later consideration" idea since step 1 is to build a FCU at home that works first. Crawl - walk - run and all that jazz.

Posted: 6/28/2017 10:33:59 PM EDT

[#13]

Ok so my idea for bending the flat with a home made sheet metal brake isn't going to work. Those mag well indents are proving to be a real bitch. They will have to be pressed like an AK flat and then bent.

Posted: 6/29/2017 1:13:54 AM EDT

[#14]

Harbor Freight's got sheet metal brakes for cheap. Even if you break one of their brakes, you can get a replacement brake that isn't broken for cheap. You could even repair a broken muzzle brake w/ a HF brake.

Posted: 6/29/2017 9:23:52 AM EDT

[#15]

Oh I got the brake made. It's tying to do the bend for the magwell that's the issue. I can bend 90 deg easily. It's the off 90 stuff that's challenging.

Posted: 7/5/2017 7:21:37 PM EDT

[#16]

Any updates?

Posted: 7/6/2017 6:35:25 AM EDT

[#17]

Quote History

Quoted:
Oh I got the brake made. It's tying to do the bend for the magwell that's the issue. I can bend 90 deg easily. It's the off 90 stuff that's challenging.

View Quote

Look into getting the HF hydraulic press, and a Swag finger brake kit for it with Hemming style dies

Posted: 7/6/2017 9:36:09 AM EDT

[#18]

Quote History

Quoted:

Look into getting the HF hydraulic press, and a Swag finger brake kit for it with Hemming style dies

View Quote

Interesting. Yeah that would be an option too. I'm going to try using my cheap HF arbor press to do the bending. A $50 purchase for a press is a lot easier for most to swallow vs a $100+ one for a hydraulic. Arbor presses can be more useful/versatile than people think. The real issue is making the dang jig. I might try doing something like this and use some 1/4" angle scrap I've got lying around.

arbor press bending

Posted: 7/6/2017 9:38:33 AM EDT

[#19]

Quote History

Quoted:
Any updates?

View Quote

Nothing of significance. Still trying to figure out how to do the mag well bends. Got a buddy with a CNC router who I'm going to work with to make a MDF protoype jig for pressing the mag well indents. Then maybe a folding jig as well. Once I have that figured out I can see about getting one made from steel. I want to try bending on my arbor press to see if I can make something work that way.

This is getting expensive

. After all it's just me, myself, and I working on this project at the moment. Balance the Army and the family life (to include a 2mo old and high energy 3yr old) there's not a lot of free time. I mostly work on this at night when I can't sleep from the pain or at work during lunch.

Posted: 7/6/2017 2:10:42 PM EDT

[#20]

Anything I can do to help? Given the pressures involved, Legos are probably not a viable option.

Posted: 7/6/2017 9:36:44 PM EDT

[#21]

Quote History

Quoted:
Anything I can do to help? Given the pressures involved, Legos are probably not a viable option.

View Quote

LOL probably not.

One thing that did dawn on me is that the poor man's ak bending jig (AKA Grasshopper jig) might just work for bending the flat vs using a brake. I did figure out how to modify the brake to work with the flat...the issue still is pressing the magazine well indents into the flat in the first place. That's the thing I'm having trouble wrapping my brain around. I have a theory, but until I can test it out that's all that it is.

Posted: 7/6/2017 11:38:21 PM EDT

[#22]

~~Wait. Can you make it a straight wall through the magwell, and use a liner to squeeze it in? We'll have to cut some plastic on the grip to fit, but...~~

N/m. Saw a pic of the FCG online from the side, optical illusion. It looked like for a moment the magwell area was thinner than the trigger area, and I got confuzzled.

Posted: 7/7/2017 5:46:53 AM EDT

[#23]

Quote History

Quoted:
Wait. Can you make it a straight wall through the magwell, and use a liner to squeeze it in? We'll have to cut some plastic on the grip to fit, but...

View Quote

I don't see a good way to do that and still keep the ejector intact. Honestly the way that I see this going is a 3 step process

1. Form the mag well indents in the flat before anything is bent.

2. Bend the flat in a jig. After thinking it over and examining my FCU closely there's absolutely no way a brake will work.

3. Use a filler block in the jig to hammer/press the ejector over, and use the edges of the jig to hammer/press the slide rails over (could POSSIBLY do this with step 1, but it makes it a bit more complicated

This is completely doable but it's not going to be a simple bing, bang, boom sort of deal. I'm honestly not sure there's a way to get around needing a hydraulic press to complete this. I'll still attempt a few more things before throwing in the towel on doing this with minimal tools. Once I get a prototype jig figured out I'll be hitting someone with a mill and machining capabilities. If they didn't take the knee mill from our armament shop I'd just go there and bribe them with a case of beer. As it is I'll be hitting up our weld shop to probably knock out the prototype jig from all the 1/4" weldable steel I've purchased for this project. I've got the idea in my head, just need to get it drawn up in a CAD software (which I suck with) or at a minimum get it down on paper and have someone assist with the CAD file.

Assuming I can get this to work...don't expect a perfect factory looking product at the end of it right away. It's gonna take a few revisions to get there. I just hope I can get this all figured out before I end up having to move in 4-12mo depending on how things pan out.

Posted: 7/7/2017 9:34:58 AM EDT

[#24]

Does the ejector have to be an integral part of the flat, or could you make it of a harder steel, and slot it in?

Posted: 7/8/2017 9:49:37 PM EDT

[#25]

Quote History

Quoted:
Does the ejector have to be an integral part of the flat, or could you make it of a harder steel, and slot it in?

View Quote

Not easily that I can figure out.

Posted: 7/11/2017 6:39:14 PM EDT

[#26]

Found an old thread on weaponeer.

Also I bought a 3D printer today and downloaded the STL files for a P250 and contacted someone about getting P320 FCU files.

Posted: 7/11/2017 6:44:31 PM EDT

[#27]

Oops.

Kinda forgot about that.

Posted: 8/1/2017 9:53:58 AM EDT

[#28]

I'm not dead or giving up. Got my 3D printer last week so I'm messing with it and trying to get it dialed in.

Posted: 8/4/2017 12:36:41 AM EDT

[#29]

Quote History

Quoted:
I'm not dead or giving up. Got my 3D printer last week so I'm messing with it and trying to get it dialed in.

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Looking forward to you taking my money

Let me know if you need some R&D funds

Posted: 8/7/2017 8:06:10 PM EDT

[#30]

Attached File

I managed to snag this P320 CAD file before grabcad took it down. Looks to be pretty accurate from what I can tell so far. Haven't had time to do an in depth comparison of heights, hole placements, angles, etc. I'm not the greatest at measuring stuff freehand. I might try rigging something up to my 3D printer to try to accurately measure the holes on my P320 FCU. I can manually move the X, Y, and Z access in 0.1mm steps....in theory. I'm having some trouble getting it calibrated.

ETA If anyone wants to get a copy of the file send me a PM. If you're able to measure your FCU against this CAD file that would be a great help.

Posted: 8/7/2017 9:08:11 PM EDT

[#31]

Or print one and see if everything fits. It'll fire at least once.

Posted: 8/27/2017 5:49:52 PM EDT

[#32]

Any updates?

Posted: 8/28/2017 5:45:13 AM EDT

[#33]

Would be interesting if someone could build one from a shovel.

Posted: 8/28/2017 8:08:07 PM EDT

[#34]

Quote History

Quoted:
Any updates?

View Quote

Well does purchasing another 320 count

? Otherwise no. Work has been keeping me really busy. Might print part of a grip this weekend to test my printer's tolerances

Posted: 8/31/2017 11:44:51 AM EDT

[#35]

http://www.thefirearmblog.com/blog/2017/08/31/khyber-pass-sig-p320

Posted: 8/31/2017 12:01:02 PM EDT

[#36]

Quote History

Quoted:
http://www.thefirearmblog.com/blog/2017/08/31/khyber-pass-sig-p320

View Quote

No joke. Those guys and the dudes in the Philippines who make guns are flat out impressive. Sure some are shit quality all around but others are really quite good.

Posted: 8/31/2017 2:14:59 PM EDT

[#37]

Some of those guys do amazing work for what they are working with. Imagine if we had a few million in tooling.

Posted: 9/6/2017 1:06:35 PM EDT

[#38]

I emailed two ppl with the 3D files. Did you guys have any luck?

I havent gotten to print the grip module yet. I have some Z banding that will throw off the print. Need to finish up my dual Z. If I have time tonight I'll set it to print the first batch of the remaining parts.

Posted: 9/6/2017 1:32:07 PM EDT

[#39]

http://firecontrolunit.com/

https://www.ar15.com/forums/handguns/New-chassis-for-Sig-P320/14-178165/

It might be ugly, but:

Posted: 9/23/2017 12:20:00 PM EDT

[#40]

Got the printer back up and running, think it is mostly dialed in now and there is no Z banding now. Printing part of a grip tonight to test fitment with my sig FCU. Then will print the STL file for the FCU and see if that fits as well as one for the 250

Posted: 9/24/2017 7:02:39 PM EDT

[#41]

PRINTed the test grip. It fits!!! Well sorta. I ended up accidentally mirroring the file. Easy fix, glad I just printed a small portion of the frame. Have some under extrusion going on.

I also ordered some grey and brown filament. My son wants a baby groot figure, and I can use the rest for gun related things. Might need to try a roll of PETG as well.

[ARCHIVED THREAD] - 80% FCG in the works (Page 2 of 2)

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