Yeah, it would seem there would be a better way to comply with Connecticut's state law that allows "machine guns" but since 1993 has generally banned "assault weapons" which "select fire" falls into that latter category.
https://www.cga.ct.gov/2013/rpt/2013-R-0050.htm
ASSAULT WEAPONS (copied from
https://www.cga.ct.gov/2013/rpt/2013-R-0001.htm )
The law defines an “assault weapon” as (1) any selective-fire firearm capable of fully automatic, semiautomatic, or burst fire at the user's option; (2) any of a list of named firearms; or (3) any unlisted semi-automatic rifle or pistol that can accept a detachable magazine and has at least two of specified features; or (4) a part or combination of parts designed or intended to convert a firearm into an assault weapon (CGS § 53-202a).
By law, with limited exceptions, it is illegal for anyone to (1) possess assault weapons, unless he or she possessed the weapon before October 1, 1993, registered it with DESPP before October 1, 1994, and received a DESPP certificate of possession for it, or (2) sell, give, transfer, distribute, or transport assault weapons (CGS § 53-202b and 53-202d). Illegal possession of an assault weapon is a class D felony, with a mandatory minimum one-year prison term. A first-time violation is a class A misdemeanor (see Table 2) if the violator can prove that he or she possessed the weapon before October 1, 1993 and otherwise complies with the law (CGS § 53-202c). Illegally transferring or carrying an assault weapon is a class C felony (see Table on Penalties), with a two-year mandatory minimum prison term or, in the case of transfers to people under age 18, an additional six-year mandatory minimum (CGS § 53-202b).