Transcript:
Welcome back to awful tactical okay today. I’m very excited to show you guys. Uh, our latest 3d printed air 15 lower. This is the third prototype, and this is the first one to actually function without any failure so far. I got 30 rounds through it right now. And without further ado, I’ll go into some more details later. I have all 30 rounds on video being fired. Uh, so we’ll watch all those right now. And then we’ll get back and talk about this all in a little more detail. Okay, guys, so I have, uh, the lower set of 3d printed air 15 lower, assembled with a classic, Uh, build kit and I’ve got just the standard 16 inch mid length gas tube upper on here. We’re going to give it a try, but first I’m going to go show you all the functionality. I will test it and show that it works. So, uh, magazine. It’s locked in press. The button. There we go magazine comes right out, so that works and now let’s take a look at the, uh, we’ll test the trigger and the trigger reset, so ill. Lock the slide back, Okay, So slide lot back. Uh, and now I’m going to drop the slide. Put the safety on, pull the trigger won’t fire. I’ll put the safety off, so safety’s right here and fired. Let’s test the trigger reset, so I’ll hold the trigger down. Well rack it. I’ll let go and little click. And I’ll shoot fire, okay. That all works great. Um, safety works. So everything’s fully functional ill. Lock it back and, uh, we’ll test fire it. We’ll shove our mag in there. Okay, so lets. Uh, let’s do the test fire so 3d printed ar15 uh, lower, uh, it’s reinforced, so we’ve got a rib right there about 100 yards right here. Give it a try, okay, and we’re about to try so now I’m going to drop my slide. Okay, we’re hot, Okay, It’s two rounds and, uh, no signs of failure yet. All right, that’s two more rounds and, uh, still, uh, still intact. No, cracking anywhere. Everything still seems to be working. We’ll test the safety again and see if that’s failing safety works. Okay, let’s fire a few more rounds. Okay, that was six rounds. We’ve now exceeded the record. The last one, which is five rounds and, uh. I have a third of our magazine here, so let’s get up. See if we get to ten rounds there. We go 10 rounds and, uh, no signs of failure, so it looks like our reinforcement has, uh, really helped. Uh, see, I’m not seeing any cracking anywhere. Uh, let’s see if I can. Uh, I’ll go prone as we can hit the little plate and see how it works there, okay here. We are same magazine and I’m going to try to hit that little plate, got it? [APPLAUSE] got it again missed. Got it, okay. We’re doing pretty good here. It was at, like, 15 rounds. Uh, I’m gonna fire all 30 for the sake of testing and then we’ll take a look at it, inspect. Yeah, I can, okay until I’m not shooting with a real ar, except that there is a view shoulder, but there’s a little flex. Still right here that you’ll notice, but other than that were, uh, we’re pretty good this. Uh, yep, were, uh, we’re open so fully functional. 30 rounds and no failure. So far. Okay, as you can see, I didn’t have any problems at all. Uh, the weapon’s accuracy wasn’t really affected at all. I was still hitting everything. Just fine, uh, like I do at the standard lower, so it doesn’t seem to be affecting that the only little the only downside I had was. It still is a little bit flexible back here. Uh, where the buffer tube is, so there’s still. I don’t think you can see that in the video, but there’s still a little flex. It’s actually kind of twisting sideways down this way because it’s got the support on one side, but not on this side because the charging panel is on the way. And you can notice that when shooting, uh, it’s slightly disconcerting. If you pull on the gun real hard, get a real tight cheek cheek weld. But, uh, it hasn’t broken at all and, uh, my, I’m very high. Hopes about its functionality and it is fully functional. Um, as you can see in the video. Uh, everything works. Just like a standard mil-spec lower. Let’s take a closer look at, uh, the lower and what I did to beef it up and get it to work. Okay, so I did have to make some compromises. Uh, when constructing the, uh, when designing a lower, uh, some of those were the two main ones. Uh, was that right here? Uh, if you can see, I’ll get it so you can see it easily on the screen. Uh, right here. I beefed this up significantly and it’s a parabola rather than a curve right here by where your with your hand goes, and it’s very comfortable to hold with a standard classic build kit like the mil spec handle, but if you try to put a magpul handle on here, it will not fit because this curve does not fit the little Tang that comes up on the handle. That’s one compromise. The other one is the rear takedown pin. You can see it’s recessed in a hole right here. And on this side, it’s also recessed. So you can get to with your fingers. You can push on it, but you have to use like a cartridge or in this case. I’ll use a pair of pliers to push it through in order to take the weapon down. You can’t use just use your finger like you can on a mil-spec one, So that’s the other main compromise, So if you give it a push, so you can get to it. And then the weapon comes apart and well. Just take the mag out now, which you should have done earlier? Um, and the front take down, pin the forward takedown pin pops right out like it. Uh, like a standard lower one. Does this one’s a bit stiff? There we go, but you can get to your fingers and there is our lower without the upper, and so you can see the main feature here. That kind of sticks out. Is this big rib right here? And what this does is It basically reinforces your, uh, your buffer tube threads, so normally all that all that stress is right here, right across this thin section here, it’s focused and concentrated. And, um, let me zoom in for you so I can give you a more close. Look, there we go. Uh, force is focused right here and it breaks. Uh, like you could see. If you look at my two previous videos, I’ll put a link right up here so you can see them. It breaks right at the rear, Take down pin and, uh, within us a few shots, so the two previous ones that broke it two shots and it broke at five shots. Um, this one here. We’ve got 30 rounds with no signs of any failure. So on so what we did to fix that problem is this curve. You can see it. This rib right here supports the buffer tube threads and so far it’s done a really good job, so the basic the idea behind this was. I can put a rib on this side, but I cannot beef this side up down here because I have the selector switch. Um, it requires a very specific wall thickness between the inside and the outside. So it has this. This plane is very important of a very. It’s gonna be a very specific place so in order to be able to operate the selector switch and have it actually rotate. So I couldn’t beef this up at all in here and you’re able to get your thumb in there. So this side on on this side on the right side of the lower, you can see it’s been significantly beefed up and I can do that on this side because I don’t have that selector, switch problem and vice versa. I cannot put this rib onto the right side because of the infamous bolt assist, which we all love so much, so we basically did what we could on both sides to stiffen it up. Uh, this works a lot lot better than just beefing it up, but we don’t. We could and so far it works, so let’s talk a bit about the post processing. I had to do after. It came off the printer. Okay, so what I had to do as far as post-processing, um, was the only support material I used on this lower. Uh, because I’m printing it once again. I’m printing it on this surface here. So it prints like this. I’ve just in the design. I’ve cut off the, uh, magazine well. The front of the magazine was a 45 degree angle and that’s the print surface, and then I put support material underneath the, uh, on the trigger guard and what what that support metal did was basically keeps it from falling over during printing. It doesn’t hold any details up. There actually, aren’t any, uh, there’s no overhang on the entire unit. Um, except in even in the holes, actually, except on the threads up here, there’s a little bit of overhang, not even overhang it’s bridging, There’s a little bridging on it. There’s no overhang on the entire receipt, drawing that the printer has to cope with the entire the reason the purpose of the support material is just to keep it from falling over during printing, propping off the bread or drooping, just because, uh, it’s so much 45 degree overhang, so this overhang does not need support. There’s no overhang that requires support material support materials there just to hold up the 45 degree overhang, so there is overhang. It’s just it’s not, uh, critical overhang, so it doesn’t need support per se to hold it up. In this case, there’s so much of it that needs to be supported and that helps more it gives more build area a bed area to stabilize the part while printing. Okay, so that piece of overhang had to be popped off. It was really easy to take off. Um, it just takes a matter of seconds. I had a couple little plastic blobs. I clicked clipped off with a pair of side cutters and other than that. The other post processing I had to do was. I got a its. Actually, I got like a 25 drill bit. Set at Lowe’s. So just your basic sizes like 15 64. Is one of them, But I took that set and with those drill bits. I was able to clean out all the holes on this. Which I which I did. The ones that I found really needed to be cleaned with a little and I drilled them out to. I think it was seven sixty-fourths. Uh, in the end, what I drill them out to. Um, I’m not quite sure about that, but I think that’s what it was. I just picked the right. The right drill bit size to match the little brass pin that keeps this, uh, captured and then I just put it. Put it in there. Clean out the flashing. That worked really well. Um, the only hole I didn’t drill out with the takedown. Pin holes. I mean, I got to take down pin holes. The, uh, action pin holes for the for the, uh, trigger and for the hammer. I left those undrilled out and I left the flashing in them. So it gives a tighter fit on the pin, which worked very nicely. I had to tap that in there and it seems very secure. And then the hole for the screw that holds on your pistol grip. I drilled that out to 15 64. So it’s a quarter 28 thread on that screw, and I just tapped into that 15 64th hole without any tap. I just put it right in there very carefully by hand, and it’s a little slow. You got to be careful to crack the plastic. Once it goes in, you’re good to go, and it’s a very secure fit, Basically like a nylock. Uh, nut it’s not backing out on you. It’s very, it’s very secure so other than that. It took like an hour to put together all that clean up. Everything and I took it out. Fired 30 rounds. No problems, uh, no errors. We didn’t have any misfeeds jams or anything on fire. No problem, so I was really really pleased with that. There’s one more thing I want to mention here, guys. And that is how the upper and the lower, uh, integrate together. As far as with this with this brace input installed and you can see the brace. Let me bring it into the camera. A little better there. We go! You can see the brace. Uh, does not touch the upper receiver at all. So there’s no interference there. I have it curved in such a way that it that it’s actually got about an eighth inch of spacing off the aluminum of the upper receiver. And then it’s, uh, this part right here is straight so that when it’s closing up, it doesn’t pop around or anything. It just goes straight up, and there’s no contact or interference. Okay, so I have the file for this available. At Hoffman Tacticalcom, I’ll put the link down here in the description to the blog post. I put up on this. I have some close-up photographs of it, and I talk about the iterations with the other two prototypes. I printed a little bit and I’ve got the files for this one. I got the solidwork files and the even got the g-code file there for the Prusa. If you want to print it on a prusa, it still needs some improvement, but right now in its current configuration, it is fully functional and it’s structurally sound. So I like to beef, put some parts of it up, For example, the magazine Well right here got a little flex to it, And once there’s a magazine in there, it holds together nicely, but that might crack if you hit the side of it, so I got to watch out for that. I want to beef that up a little bit, and there’s some other little details, But as far as functionality goes, it’s it’s pretty much watching. Watch 100 the failure mode. I think is going to be rather than when it’s firing breaking, just carrying it around if you drop it or you hit it on something you’ll break off there, you’ll break your stock off. I think it’s gonna be the failure mode. Uh, but we’ll find out and I’ll update you guys on the status of this once. I get a few more rounds through it and give it a little bit more wear and tear. Hey, if you enjoyed today’s video on this, be sure to hit that, like button down below. That really helps get more views. Uh, brings more people to the video. I think this is an interesting subject so comment. Uh, what you think about it? Uh, if you have any experience, 3d printing ar15 lowers, uh, be sure to let us know what you think. And any improvements we can do and I’ll see you again later.