Complex sentence: These are fairly rare in the United States firearms market because they were banned from further importation in 1989 by an executive order from George Bush and thus command prices far in excess of the original MSRP usually ranging from $2000 to $4000.
Split into simpler sentences: These are fairly rare in the United States firearms market because they were banned from further importation in 1989 by an executive order from George Bush. Thus they now command prices far in excess of the original MSRP, usually ranging from $2000 to $4000.