Yeti Wurks has been making 3D-printed upgrades for the CZ Scorpion Evo3. One of the items they make is a US-made 3D printed magazine base plate. They even made a +3 mag extension.
I reached out to Eric of Yeti Wurks and asked if he could modify his design and make the extension longer to add 10 rds to a 30-rd Scorpion magazine. He said that he had dabbled with a +10 extension but wasn’t able to get it to work because he did not have a spring that could work. However, I did. So he sent me his first prototype.
Unfortunately, that prototype did not work. The channel for the extension was in the wrong position so the follower could not slide down into the extension. Eric redesigned it and sent out another prototype which you see in the photo below.
Since it is 3D printed and only a second prototype design there are still some issues to work out.
There is some slack with the position of the extension in relation to the mag tube. If the extension is pushed all the way rearward, the follower cannot slide down into the extension. So I shimmed the extension at the front leading edge of the mag tube. Once properly aligned, the follower can travel up and down without issue. The corners of the extension were a bit sharp so I filed them down to allow for smoother operation.
I ran the Scorpion and this specific magazine with the printed extension in a USPSA match just last weekend. It fed the Scorpion Evo3 flawlessly.
While testing the magazine extension, a small hairline crack was seen along the side of the magazine extension. So back at Yeti Wurks, Eric is going to redesign the extension and make it more robust. No details on price or availability just yet.