3D Printed Free Float Rail

[depletedyourcranium]

I've been trying to shed some weight where I can without spending too much money on my lightweight build and thought I'd try with a 3D printed plastic handguard. I've also had an issue with the aluminum rails getting very cold on hunts and figured this would also alleviate that issue as well.







My brother did the printing but I did the CAD work. So far the 7 inch plastic tube will save .48 lbs over the 15 inch aluminum ALG rail, which was already pretty light. The plastic rail weighed .19 lbs, which is about half of what a similar length aluminum rail would weigh.

I think the final design will extend on out past the gas block and include a few strengthening ribs along the base. When I get the next one printed I might try a little stress testing on the old one to see what kind of abuse it can take. This one was printed with PLA and is very rigid, works pretty good at staying off the barrel even with the close clearance.

[Sixoeight]

Pretty cool. Might want to consider some sort of epoxy coat just to make sure the layers are bonded permanently.

I don't have a lot of 3D printing experience but with the extrusion systems the biggest weakness is the poor bonding when the next layer is laid down. You could also try SLS or even better SLA printing which doesn't have this problem as much.

Cool idea though and great CAD work.

[FRB6.5]

Looking good! Please keep us updated as to how well it works.

[jhoyda]

How many rounds do you think you can fire before the plastic softens due to heat?

How stiff is the handguard? Can you hold it while shooting?

[depletedyourcranium]

The handguard feels as stiff as the aluminum it replaced. Theres no perceivable bend or movement when pushing on it. Heat is the biggest concern since it is a thermo plastic. PLA starts getting soft around 140° F, so it wont take long to reach that, especially around the gas tube. I would say I would get have to worry about serious softening after about 10 rounds fired in short succession. So definitely not something suitable for most applications in a semi auto rifle, but for hunting I think it will do.

EDIT TO ADD: I should also mention that my ultimate goal is to print the final version in nylon which will have much greater durability and temperature resistance, something I could probably dump a mag with and not have to worry about melting. Prototyping in the PLA is just much cheaper and easier at the moment.

[bj139]

This looks like an expensive version of Schedule 40 PVC pipe.

[depletedyourcranium]

3D printers sure can run up in price, but the actual cost of printing is super cheap. I could get my brother to quote me the specifics, the splicer programs will calculate the cost of each print based on the amount of filament used and the electricity costs of operating the printer, but I would be shocked if this cost more than $2-3 in material and power.

[bj139]

Can you 3D print a picatinny rail on top and bottom for FS and bipod? Would the strength be enough?

I just noticed the one piece lower and stock. That is nice. Did you 3D print that?

[depletedyourcranium]

Can you 3D print a picatinny rail on top and bottom for FS and bipod? Would the strength be enough?

I just noticed the one piece lower and stock. That is nice. Did you 3D print that?

Yeah you could print rails and pretty much whatever you wanted on there. Depending on the orientation of the print and the kinds of overhangs, though, they may not print well or would require some extra finishing to remove support material. They would be strong enough to clamp to, but something like a bipod I think would probably overwork the material and lead to eventual failure, I believe.

The lower is a GWACS Cav-15 polymer lower, bought not printed. It would be totally possible to print one, though, if you had the right printer and could replicate the design in some CAD software. If you were able to do it in something durable like nylon I think it would also be almost as durable.

[jhoyda]

Can you 3D print a picatinny rail on top and bottom for FS and bipod? Would the strength be enough?

I just noticed the one piece lower and stock. That is nice. Did you 3D print that?

It would not be strong enough. Ok, maybe if you printed the tube thick enough. But that defeats the purpose when aluminum handguards readily available.

3D printers are great for mock up and prototyping and the cost of entry is much lower than say a HAAS VF-1, but in terms of actual useful and durable parts they are quite limited.

[depletedyourcranium]

I'll have to respectfully disagree on your last point. No, of course you can't print just anything and it be better than modern manufacture. But as long as you're working within the constraints of the material, the only limit is your imagination.

This handguard is working outside the parameters for the material so it's not a great example. However, one of my carry guns is currently sporting 3D printed sights and magazine floor plates. I have tried within reason to get them to break and have failed. I can rack the sights off my belt and drop release the mag onto cement and it functions as well as the factory parts. And this is for a gun that pretty much has no aftermarket, so if I weren't designing my own I would just be stuck with the OEM setup.

[Sixoeight]

Pics? Sounds interesting

[depletedyourcranium]

The floorplate is nice improvement over the factory. The sights were an experiment that didn't pan out. They're functional but a little slower to pick up than traditional notches. I'm currently redesigning them into a wide V notch something like the XS sights.

[Sixoeight]

Pretty cool. A little bit of sand paper and a vibratory tumble and they could look like aftermarket parts.

Next step: print reliable high capacity grendel mags haha