+1 for Ed. If you can not SBR a rifle in your state, then you have to get something that was registered as a pistol by the orginal manufacturer. In the case of building a clone, the receiver must have been registered by the mfg as a pistol.
There may be a way to take a Title-1 rifle and re-register it as a pistol so that you can convert it in non-SBR states, but I do not know off the top of my head. I would contact your State Police first and check with them as typically, State law is more restrictive than Federal law.
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