If you cut the circumference strands off of the conductor...you win a red sticker.
Yes there are adaptors made to "fit" larger wire into "factory" lugs...and the AHJ should find them acceptable if the conductor size was increased to voltage drop, ar a different material (Cu to Al). Bending radius has to be considered also. Usually, the job plans reflect VD calcs, and if a larger conductor is required, the PE/EE specs larger lugs.
John
