AR15

https://www.slideserve.com/bendek/ballistics-and-zeroing

Unfortunately the Slideserve website this is hosted on won’t let me download this powerpoint presentation, so you will have to read it at the link above.

There is nothing new or special in here, but it is a nice primer on trajectory and M16/M4 zeroing.

Sometimes 3D printing is as easy as selecting a .stl file, pressing the slice button in your slicer, then hitting the print button.

Sometimes it isn’t.

I had some old printer filament that used to print wonderfully. I pulled it from storage and was trying to print with it. The layers were delaminating and it did not want to stick to the print bed. Likely the filament absorbed moisture during storage and is no longer good. So I opened up a new roll of marble filament.

This is the time I learned about the Hellfire lower, so I start printing one.

The nozzle clogged partway into the print.

I had been using that nozzle for a while, and it was overdue replacing, so I replaced it.

I had to re-adjust the height of the print bed after doing this.

Then I was able to print the good lower.

The Hellfire lower prints with a minimial amount of pre-made supports. It cleaned up rather quickly and mostly easily with a pair of plyers and a scraper tool. There were a bunch of little zits, blobs, and stringing in the magwell that cleaned easily. It was much easier to clean up than the slicer generated supports on that other lower I printed.

As I started printing the other parts, I had issues with bed adhesion. The parts filament absolutely did not want to stick to the bed of the printer. I had to cancel most of the prints a few minutes into them it was instant failures.

This part, for example, started good. But once I left it unattended it turned into spaghetti.

The rear of the receiver took two tries to print. Most of the others took several more.

During these prints I increase the amount of material in the first layer, and moved the nozzle closer to the print bed in an attempt to fix this.

I print on a mirror. I ended up bring in the nozzle too close and scratching up the mirror. So I threw away that mirror and installed another IKEA mirror that came in a pack of several.

The lower wasn’t the cleanest or best print. There was a little bit of poorly overhang filament that was preventing the rear of the receiver from installing. A moment with the scraper cleared off that plastic and allowed the rear of the receiver to slide on.

The two bolts seemed to me that they would hold on that section well enough. But I’m not sure how it will hold up under stress.

When the prints would stick to the bed, they still weren’t sticking well, and the would curl upwards away from the bed of the printer.

Despite this warping of the bolts and parts, they still went together easily.

If I could sing, I would sing complements of this design.

For the most part, I was able to assemble the lower like a standard AR15 lower.

The front takedown pin is extremely hard to open and close. Because the detent goes though a piece, it tends to hang up there causing me to struggle opening and closing it.

While I was working on it, I did the foolish thing of dropping the hammer with out the upper installed. This is something you are not suppose to do on a standard lower due to the chance of damaging it.

Immediately cracked the lower.

If the bolt catch had been installed, that might have provided the support necessary to prevent that area from having cracked. But either way, that won’t prevent function. I’m just going to leave it broken. I might rip out that chunk before I install a bolt catch.

This lower is somewhat rigid, but I can grab it and twist it a little, flexing it. I’ve read some people report their fire control group pins drifting out using use.

I don’t imagine this lower would last forever, but I have no doubt it would work. As for ergonomics, the thicker lower section where there are two bolts holding on the rear of the receiver extension makes the gun a little less pleasant to handle. But not terribly so.

Ignoring the various printing problems I ran into (that are not the fault of the lower), this has been one of the easiest 3d printer projects I have done. If you were new to 3d printers and wanting to print a lower, I would recommend this one.

I’ll probably go ahead and print another, nicer version of this lower sometime. But for the moment I am happy enough with how this one turned out.

I was surfing the web and I came across a picture of this:

This is the Anderson Wildfire, a 3D Printable AR15 lower designed to use standard parts, including take down pins.

I find it interesting the design changes to make it more successfully printable.

Unfortunately with this design, you would have to remove one of the screws to pivot a side reinforcing plate in order to disassemble the gun. I also read that this lower is lacking in rigidity. Still, I decided I was going to print one.

UNTIL. . .

The very next day I found out that a new and improved version had been designed and released.

The Anderson Hellfire.

I found out that the data package is over on Keybase and I went and downloaded it and looked at the design.

Lower design aside, the documentation and design files of this project are superior to most every business and professional project I have worked on or seen.

I had to make one.

Now, just a quick word of warning. The main model in the Hellfire is designed as fully freedom. Depending on what you are trying to accomplish, you might want to print the alternative, semi-free model.

The Wildfire, and the Hellfire lowers are printed in several parts. Partially due to limitations in 3d Printer capabilities, to maximize the strength of the parts, and to make it easy to replace broken parts.

As an attempt to better secure the area where the buffer tube screws into, the Hellfire uses two bolts to hold it on to the rest of the lower, and a third bolt to (uniquely as far as I know) put tension on the top left while the bolts hold in compression on the bottom and bottom right.

I have no idea how good it will work, but let us give it a try.

Tally Ho!

It was nice timing for me on this one.

P&S, a government contractor that supplies items like stocks, rail systems, and more, have had their version of the M4 Waffle Stock in general issue now.

The first major issued stock for the M4 is known as the “CAR” stock. The “Waffle” stock replaced it, and had a slopped butt, metal bottom sling swivel, and reinforcements that gave it the waffle appearance that lead to that name.

This P&S version of the waffle stock omits the bottom sling swivel and adds a quick detach (QD) sling socket near the front.

These stocks have been available for years from multiple vendors. The one in the picture above I purchased from Damage Industries. Colt even put these stocks on their Colt Competition Rifles for a limited time. Even Anderson had a rebranded version. Some of these have little differences in markings, but they are the same product made by the same company.

So why did I buy one?

There are a wide variety of QD mounting options out there.

In my opinion, the relatively new QD mounts that replace the receiver end plate provide a perfect spot for mounting a sling. The sling attached in a way that works great for when you are moving fast or transitioning from dominate to non-dominate side and back.

The much older Knights Armament sling mounts looks awesome and I love the profile of it. But I have had QD sockets there rub up against my hands and cause discomfort. You wouldn’t think that would be an issue with that location, but I have had that problem. I’ve also heard of cases where it interfered with collapsing some aftermarket stocks completely.

The P&S stock is sort of an odd duck. The QD placement is farther from the receiver than other options.

I’ve only spent a few minutes handing it and trying this setup with a sling and while it works, I would say it is inferior to the QD receiver endplate. Having the sling swivel on one side of the rifle or the other doesn’t cause an issue when you are transitioning shoulders, but if you have the sling swivel on the outside socket of the rifle, it may want to flip around when you are carrying the weapon by the sling with out a hand controlling it.

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Realistically, if someone were to ask me what the best sling solution would be, I would recommend getting a QD mount receiver endplate but any of the numerous companies that make one. (Other than Damage Industries, the one I got from them was garbage https://looserounds.com/2018/10/31/damage-inc-llc-qd-end-plate-sucks/).

But if for some reason you couldn’t or didn’t want to modify your firearm, this stock might be a great option.

I had been considering installing a QD receiver extension on my Colt 6945. I really didn’t want to break the factory staking on my Colt 6945, and I normally run a waffle stock on it. Upgrading to the P&S waffle stock with QD swivel is a big improvement there. Perhaps not as good as other options, but good enough to hold me over.

I had forgotten this option existed. When I learned that the military now has this stock in the system, it got me thinking about it. So I am going to use it for now. I might still switch to a QD endplate someday, but not today.