I have been incapable of finishing a decimator build with an OEM barrel; 2 different OEM barrels as a matter of fact.

I’ve reprinted the upper twice (once because I wasn’t sure if I just really messed up the print, once for stripping barrel nut threads) and I’ve reprinted the barrel nut 3-4 times at this point.

I started this build just before fosscad was nuked, and since the Ark is back up (https://forum.guncadindex.com/c/ark@fosscad.io), I was able to see that there are threads where others have had this issue.

Has anyone overcome this issue personally? The build looks great and I love the AR fcg but I’m hitting a wall here. Should I just drill and pin the barrel nut with a couple of set screws?

  • hoglegOPEnglish
    2·
    2 days ago

    I wanted to make sure I updated this for anyone following down the road. I didn’t realize what the problem was until I printed the actual R2 Galileo barrel nut and compared; the hole for the barrel on the R2 was much wider than the Decimator v3. I dropped a 23.2mm negative cylinder into the center of the Dv3 barrel nut and it resolved the problem. I’ve not got any experience with printed barrels to compare, but I imagine their OD is narrower than the widest portion of the factory barrels I was working with.

  • notsuspektEnglish
    1·
    29 days ago

    Join the DD rocketchat and talk to Decimal yourself, he’s an awesome guy.

    Before doing that, calibrate your printer. The upper/barrel/nut interface depends on some pretty narrow tolerances.

    • hoglegOPEnglish
      2·
      29 days ago

      Thanks! I’m dialed in on flow ratio, pressure advance, e-step, as far as I can tell and I’ve got several other successful prints. None of them using printed threads like this, though. I’ll see if I can bend his ear about it.

      • notsuspektEnglish
        1·
        29 days ago

        If I recall correctly, he oriented the barrel nut super weird, with the bore facing sideways. I did mine vertical and it threaded on fine but he had a good reason for that orientation.

        Have you done dimensional calibration, like a calilantern?

        • hoglegOPEnglish
          2·
          29 days ago

          Yeah, I ran into the same thing with the orientation; got farther after orienting it vertically, but like you said, he had a reason for the original orientation.

          And I have not done that; I’ve never even heard of the calilantern. I will for sure give that a go. Thanks!

          • notsuspektEnglish
            1·
            29 days ago

            It helps a lot with threads, and under/over extrusion. If you need the files DM me, you’re not supposed to share them cause OP has cancer and he sells them.

            • hoglegOPEnglish
              1·
              2 days ago

              Hey, thanks again for the assistance! I didn’t get back to this for awhile; life things. I left an update up at the top for anyone in the future.

            • hoglegOPEnglish
              2·
              29 days ago

              I appreciate it! I’ll throw him a few bucks for his work and guide. Wouldn’t want to see that become standard in fosscad or a lot more people would end up losing fingers, I think :p