Scorpion Evo3 +10 Rd Mag Extension

I have been working with Eric of Yeti Wurks. More like hounding him with requests to make me one more than anything else. Eric has made a name for himself making 3D printed upgrades for the CZ-USA Scorpion Evo 3. His grips are amazing. He has dabbled in making US made base pads and even made a +3 rd extension. I reached out to Eric to see if he could extend it to add 10 rds. He told me he had tried and sent me his prototype. Unfortunately it didn’t quite work and needed some tweaking. One of the biggest issues was getting a magazine spring that would work and feed the 40 rds of 9mm. I had some springs that could work. Here is the second prototype and it works flawlessly. There are a couple issues that are being corrected now and I am waiting on the third version of this +10rd mag extension. FullSizeRender IMG_4379


I test ran the mag at a local USPSA match.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at


  • Markbo

    Any reason it is white and not black or smoked???

    • Retriever222

      Probably because it was a prototype. Also translucent materials are inherently weaker compared to opaque materials.

    • Steve Truffer

      White filament is easier to spot print flaws in, so if there’s any separation/cracking, white should show it better.

  • CO ED

    Now make a +5 so those in Colorado and New Jersey can have 15 rounders and you’ve got a market. Also the longer spring can come from a 20 rounder solving that problem.

  • Lee Enfield

    Hmmm…with the magazine lips cracking issue with regular EVO mags I wouldn’t think putting maybe even more force against them would be a very good idea. Just saying.

    • Malthrak

      That’s been resolved for many months now, almost a year. It was pretty much a single run from early 2015/late 2014 that had the issues. Earlier and later magazines dont appear to have the same issues.

      • Nicholas C

        Yep. None of my mags have cracked and I got an early one.

        • Cope

          FWIW, I sent back 9 cracked feed lip mags today. 5 are from January of 2016, and were all loaded and shot once, reloaded and then left to set for 3 days (looked this morning and every one of them had cracked feed lips). I had 4 that I called about which were cracked and from November of 2015. Anyhow, apparently the January ’16’s crack also. I do have 1 from November 2015 which has yet to crack.

          • Malthrak

            I’ve got a bunch from August & November 2015 and several from April 2016, all have been shot at least twice, the 2015 ones probably a dozen times each (I’ve put about 3.5k rounds through the gun so far, not a gargantuan amount but decent number), several left loaded for a couple months while I was out of town, I haven’t had any cracks yet, though none are from Jan of 2016.

          • Lee Enfield

            It’s a real pain but it sounds like I’m going to have to go through the same process that Cope did and test fire and load test all my mags. Plus I’m gonna have to do it soon because come November I’m guessing that there ain’t gonna be a high-cap mag to be found.

          • Cope

            Loaded 5 good mags to shoot yesterday but didn’t get a chance. Today, 4 are cracked at the corner below the feed lip on the side the top round is retained. One is 11/15, and the other three are 02/16 vintage. Starting to think the only way to leave a mag loaded is in the scorpion, so the bolt takes the tension instead of the lips. . . That or we need some sort of feed lips detensioning cap like pmags used to come with.

        • Lee Enfield

          So what is the deal with deleting posts that may go slightly counter to the editorial position?

          I saw the post above from Malthrak and Nicholas C and then I post the fact about the CZfirearm thread about people having cracked mags from Jan2016.

          Then lo and behold my post gets shoved down the memory hole.
          Can you kindly explain the rational of deleting my post?

          The only possible rationale is that I see Cope now put his comment in here versus the link I had to CZfirearms and that maybe you didn’t want repeated info. If that is the reason then I’d say that’s some pretty aggressive maintenance cleanup and that it may tend to perturb posters… just saying.

    • Kelly Jackson

      That hasn’t been an issue in months, are you still worried about the Ottoman empire grandpa?

  • imachinegunstuff

    Yeti works also makes some awesome mag pouches for the Scorpion and sub guns in general.

  • Kelly Jackson

    I’d also run rapid fire and the laser

  • Nicholas C

    Actually this is not filament. This is SLA printing.