I have an FNC and I like it  but the slab side lower doesn’t look the part. I remember years ago there was a company that was doing some work to update the FNC and I think they improved the look of the lower with a mag and mag release fence.
Could a fence be made up on a 3D printer and then applied with a quality adhesive? I’m not too knowledgeable about the material used in the printing but I bet there is some polymer that would work.
Thanks for looking.

Do not defile your factory fnc lower in such a way.

Yes it could be done but I would use a double sided tape type of product to adhere it.

It is my understanding that the lower is not the registered part. Couldn't you just have a lower 3D printed? Of course the engineering costs would make it very expensive for a one off. If you do decide to do that, I would send documentation to show that what you want printed would not come under the Gun Control Act of '68. I had a finalized version of an an M16 adapter for the M10 printed before going into aluminum production. We had made several revisions and that was cheap insurance that all the changes made it into the latest version. Protolabs wanted documentation that the adapter did not fall under the GCA of '68. We had submitted the proof of concept and had a determination from the FATD that stated the adapter did not fall under the GCA.  The Protolabs representative said they have been inundated with orders to print AR style lowers and handgun style frames. Luckily we got the original design done. A 3D version of the adapter costs us $500. A one off aluminium version would have been well over 10 times that. Good luck with your project.

Scott

FYI, at least on the FNCs I have inspected, the magazine release spring is way stronger than the one typically found on an AR15.  I have looked for a higher tension mag release spring to use on my Sig 556 as I had put the extension on it to for better access and wanted it to be less susceptible to being bumped,  I couldn't find anything close to being as strong as the FNC.

I can't remember for sure if I tried doubling them up, but if I had they probably didn't work as intended.

I would avoid any milling or work on the actual lower.

If done right you could create some sort of polymer product that slips, clips, or is glued on to help give it a littler extra visual appeal.

That’s what I’m thinking. A polymer piece that I can glue on.