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The only option I see is to apply for a short-barreled-rifle tax-stamp and then installing the Sig-Sauer Stabilizing Brace using an adapter for such purpose. You don't need a tax stamp to use the brace as only an arm brace. You must wait for the tax stamp to arrive before using the brace as a shoulder stock legally. Contact a local Class III dealer near you to apply for the tax stamp and check with them about any state or local laws that may also apply.
With the brace up against your shoulder, like a stock, you can rest your cheek on the brace for sighting purposes.
Here is a video showing the Scorpion being used with the brace as just a brace and then as a short stock. Skip to 5:55 into the video:
Link to video
I hope this helps.
Yes, the 922 r compliance would be an issue, since it would then be a rifle. However, there is a 922 r kit for that gun.
Turns out that CZ has a 922 r compliance kit, that includes a pistol grip and a folding stock for that pistol to turn it into an SBR. Here is information on that. I would contact CZ about availability. You need the stamp and probably a gunsmith should do the conversion once you have the stamp and kit, if you want to go that route.
Link to kit
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