 The basic SR9 is fitted with a reinforced fiberglass thumbhole stock containing an MSG90 buffer.The 1989 Import Ban, enacted by President George H. W. Bush, bans from importation all semi-automatic rifles with a folding or telescoping stock, separate pistol grip, bipod, ability to accept a bayonet, grenade launcher, night sights, or flash suppressor.The HK91, HK93 and HK94 models were all on the import ban list.