Complex sentence: A non-machinegun that may be converted to fire more than one shot per trigger pull by ordinary mechanical skills is classed as a machinegun, such as a TEC-9 pistol (pre-ban ones are "grandfathered").
Split into simpler sentences: A non-machinegun that may be converted to fire more than one shot per trigger pull by ordinary mechanical skills is classed as a machinegun. Such as a TEC-9 pistol (pre-ban ones are "grandfathered").