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Which Lower Reciever would you be interested in seeing built this year?

Poll for the next XCR Lower project!

3444 Views 66 Replies 8 Participants Last post by  Chowwow
New year, new start on a fresh, challenging projects!

Work on the AR-XCR lower is drawing down in terms of CAD work, though the transition to CNC machining will require it's own steps. In the mean time, I believe it is time to move forward with the lessons and tools we've gained over the last year of work and produce a new lower for the XCR family. After some thinking, I've compiled a list of possible projects that I can move forward with, and I would like to know which of these ideas have popular support so that I may focus my efforts on a specific project. Here are detailed descriptions of the projects with pros and cons to each one:

AK-XCR with XCR TriggerAn 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.
  • + Low profile and light design
  • + AK magwell specifications are publicly known
  • - Requires designing proprietary mag latch; one that is longer and in a different position than the standard mag latch used in the AK. Will require trial and error.
  • - No BHO unless Yugo mags somehow work.
  • - Must purchase standard AK mag to ensure compatibility.
  • - I do not personally own 7.62x39 barrel conversion. However, I do own a 6.5 Grendel barrel conversion, which uses the same bolt and enough 6.5 Grendel rounds can be loaded into an AK mag ensure function.
AK-XCR with AR-15 TriggerA 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.
  • + Uses AR-15 triggers! No longer dependent on RA for triggers
  • - No BHO
  • - Requires designing a unique mag latch that is different from the one used in the previous proposed design. It must be longer to accommodate the extra height imposed by the AR trigger group. Position of pivot pin will be different too.
Swappable Magwell XCR lower with AR-15 TriggerA 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.
  • + Feature rich, one and done solution
  • - Complex, and requires careful machining
  • - Development of this system basically involves developing an AK-XCR w/ AR FCG anyway, with further development on the magwell swap feature added at the end. Might be worth holding back development until other designs are proven.
AR-XCR-MEverything 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.
  • + Added features for the -M, mainly the option to use your own dang trigger for your -M
  • + Expected design will be similar to the AR-XCR(-L), just with the expanded magwell
  • - Not sure if expanded trigger options are necessary for the -M
  • - Might need to design a new BHO
  • - I do not own an XCR-M (yet), and I need to acquire one and go through the same process as I did on the AR-XCR to ensure the function of the design
Bren-XCR with AR-15 TriggerA 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.
  • + Design (potentially) will be very similar to AR-XCR and can be made relatively quickly
  • + Similar ergos and functions of AR-XCR
  • - Requires extended BHO (hopefully the same one used in the AR-XCR and AR-XCR-M)
  • - May require longer Mag catch (maybe the one on the XCR-M?)
  • - User becomes reliant on CZ to release these magazines in his country. Will be incompatible with AK and STANAG mags.

This thread will be edited to become the build log for the winner of the poll. As it was in the last thread, I expect to have major CAD work done by the summer, and something built in metal by the winter. Your opinions are welcome!
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I'm also very interested in an XCR-M lower but figured anything on the L platform would probably happen sooner since you started with the L-1913 lower.
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Just my 2 cents, the bren mags would be a lateral move and not offer any distinct advantage over the existing stanag x39 magazines, I'm doubling down on my ak mag vote, for the mass availability. Also I like the price point of ak mags much more. $30 mags was a lot of what I didnt like about the existing Robinson x39, I don't think another expensive and hard to find magazine is the right solution (atleast for me), unless one already has a bren2 and is already invested into their magazines.
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Agreed. An AK mag is the draw. It's a completely reliable, inexpensive and ubiquitous solution to the problem of feeding tapered Russian ammo.
What I was trying to say but my brain just kept going "uuuuuugh." while I drooled on myself.
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Those are valid points, but truthfully I just want an ak mag lower. That would make me very happy.
Sean, you sent me down the bren rabbit hole again. I then got less excited when I couldn't find any available other then a couple of 9" ones, paired with having to monkey with the gas plug, it seems like it has a lot of feature that the Robinson has but I feel like cz "missed it by that much" with the bren.

Although lingles lower is finally in-stock, been looking at them off and on for a year plus and I felt like every time I would look they were always out of stock. I had also been eyeballing their stribog lower but had issues with putting 2k-ish into a 9mm build. When I could get a real rifle for that kinda $$$.
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No more new voters? I know the community is small but are all the new members bots?
@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!
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