I spoke yesterday with a California DoJ in-house SB23 analyst regarding the effects of the Fed AW Ban sunset's effect on SAW's in Calfornia.
She confirmed the following:
1) The California bans are still in effect after the Fed AW Ban sunset (as suspected). All firearms banned by Roberti-Roos, Lockyer v. Kasler, and SB23 remain banned--no newly manufactured or imported AW's (by the aforementioned legislation's definition or listing) are permitted after Jan. 1, 2001 to enter the State.
(Note: there exists an SB23 exemption written in for military personnel being transferred to California--requiring an application, fee, and background check to register personally owned AW's.)
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2) The California DoJ does not recognize the now-dead Federal AW Ban's concepts of "Pre-" and "Post-" ban. Under California law (Roberti-Roos, Kasler, SB23) either a firearm is or is not an AW, regardless of the number of banned features.
That's the straight info dump from the DoJ.
So, "yes", in California you can reconfigure our SB23-registered rifle into "No-Ban" configuration--because, as mentioned above, the California bans don't limit the number of banned features. (Note: all Federal NFA and 922-R rules still apply!)