Have you decided to go with polymer mags only to avoid having to sleeve the internals of the lower?
AK-XCR with XCR Trigger | An offshoot of last year's Picatinny-XCR lower using factory-standard AK magazines. This will be a CNC machined lower featuring a rear 1913 rail for stocks, the original XCR trigger group, and a low profile magwell and mag latch for the AK magazine.
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AK-XCR with AR-15 Trigger | A variant of the AR-XCR lower that uses AK mags. This will be a CNC machined lower featuring a rear 1913 rail for stocks, the expanded body for an AR-15 trigger group, and the AK magwell and mag latch.
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Swappable Magwell XCR lower with AR-15 Trigger | A variant of the AR-XCR lower that has all of its features as well as being able to swap out the magwell of the lower from a module that accepts AR mags and contains the BHO, to one that accepts AK mags and contains the mag latch.
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AR-XCR-M | Everything that I've done for the XCR-L, but with the lower for the -M. It will be a CNC machined aluminum lower fitted for the XCR-M that accepts LR-308/SR-25 magazines, a rear 1913 rail and an expanded body for the AR-10/AR-15 trigger group.
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Bren-XCR with AR-15 Trigger | A variant of the AR-XCR lower that uses 7.62x39 CZ Bren 2 mags. This will be a CNC machined lower featuring a rear 1913 rail for stocks, the expanded body for an AR-15 trigger group, and a magwell accepting the Bren 2 mags.
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No, that was what was available at my LGS and I just needed something that was dimensionally accurate to work with. I ultimately want something that is universally compatible with all AK mags. I never heard about sleeving a magazine well and I've been trying to look it up. I understand that the mags are steel and the upper will be aluminum, so I imagine it will be necessary to prevent gouging. I've never seen it being done though and I can't find any examples yet. Do you know where I can find more info?Have you decided to go with polymer mags only to avoid having to sleeve the internals of the lower?
That's going to be the problem most likely. The aluminum lower receivers that I can think of that took steel AK mags had to put a steel sleeve in the magwell to get them to work reliably and not wear out the receiver. The Sig 556R was a notable one. M+M Industries M10X uses one too IIRC. I'm sure there are others. That's the problem with an aluminum lower and steel mags.No, that was what was available at my LGS and I just needed something that was dimensionally accurate to work with. I ultimately want something that is universally compatible with all AK mags. I never heard about sleeving a magazine well and I've been trying to look it up. I understand that the mags are steel and the upper will be aluminum, so I imagine it will be necessary to prevent gouging. I've never seen it being done though and I can't find any examples yet. Do you know where I can find more info?
I'll either make a design that consists of a press-fit mag well sleeve that is secured by two pins, or keep it to aluminum with polymer mags for now. One could machine a steel mag well sleeve, but it would cost a lot of metal and tool deflection could affect the dimensions. An extruded steel part would be the most consistent but I would have to buy hundreds or thousands of them. And here I thought this project was gonna be easy...The aluminum lower receivers that I can think of that took steel AK mags had to put a steel sleeve in the magwell to get them to work reliably and not wear out the receiver. The Sig 556R was a notable one.
You know what? I've decided to keep it simple and stick to making the AK-XCR lower all aluminum and just advise that users use polymer mags with it. It's just that making a steel sleeve that press-fits into the receiver appears to be technically out of my reach in the near and mid-term; with the type of milling machines available to me, I don't see how I can build a steel sleeve accurately and consistently enough to get good results. Steel extrusions would be the best part for this kind of job but I don't have the tech to build my own steel extruder or the money and space to order thousands from a supplier. Instead, if/when I design the swappable magwell lower, I will make the entire AK magwell section out of steel that will pin to the other half of the lower and that assembled lower will gladly accept steel mags.Have you decided to go with polymer mags only to avoid having to sleeve the internals of the lower?
If metal AK mags are a no-go...I wouldn't bother making this lower TBH. You're probably better off designing for the CZ Bren 2 mags.....but that's going to be pretty boutique once again.You know what? I've decided to keep it simple and stick to making the AK-XCR lower all aluminum and just advise that users use polymer mags with it. It's just that making a steel sleeve that press-fits into the receiver appears to be technically out of my reach in the near and mid-term; with the type of milling machines available to me, I don't see how I can build a steel sleeve accurately and consistently enough to get good results. Steel extrusions would be the best part for this kind of job but I don't have the tech to build my own steel extruder or the money and space to order thousands from a supplier. Instead, if/when I design the swappable magwell lower, I will make the entire AK magwell section out of steel that will pin to the other half of the lower and that assembled lower will gladly accept steel mags.
In other news, I was able to buy the mag release and associated hardware for the CMMG MK47 from CMMG's customer service. Cost me $38 and some change. This'll help a lot with this design job, though how I intend to include one for each of the production lowers isn't something I'm thinking about right now. I suppose I can copy the design of this mag release or something similar when the time comes. Still, it's nice to know that we can rely on a major company to be producing a critical part for this lower.
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Was giving this some thought and got an idea: making the walls of the mag well out of four thin (.050") steel plates that interlock with each other like those Lincoln log toys that are press-fit from the top into the aluminum lower. There is not much space or material to work with but that might work without the need to bulk up the design or needing pins to secure it.If metal AK mags are a no-go...I wouldn't bother making this lower TBH. You're probably better off designing for the CZ Bren 2 mags.....but that's going to be pretty boutique once again.
Right, corrected. The overall thickness of the sides of the mag well wall is about .155". There is not a lot of material to work with there, but I think it's doable..050"?
One step at a time, let's see when my -M finally comes in!My choice is AR-XCR-M. Please take my vote into account👏
I remember seeing that and figured it was temporary reinforcement until he had the design refined. I'm trying to keep the design as light and refined looking as the CMMG MK47 rifle. I don't think it's going to be necessary in my design though it kind of bothers me that the magwell is so thin while still needing some thickness for that steel sleeve. I'm hoping it doesn't look to ballooned out in the end; otherwise I'm enjoying how small and light this model is.@Chowwow the prototype lower looks great, so something else that abran007 did on his was extend the right side of the receiver down similar in shape to a fal receiver, I'm not sure it would make the magazine set anymore secure like as in left to right wiggle, but it sure looked cool. Either way seeing an xcr upper with a lower that takes ak banana mags is awsome!
Something like this almost did happen before I came here, though it was never mass produced. Even without abran007's data, I walk on his footsteps and make my own in time. Progress will be relatively slow until I have the AR-XCR in metal in front of me. It will hopefully be more efficient now that everything behind the magwell is confirmed to work thanks to previous research. I think I'll print the next AK-XCR after I'm satisfied with the last things I need to do with the AR-XCR.I remember seeing this idea on this page a while back, and thought it would never happen. Now look where you are. This is some crazy progress.