The Shooter's Butt Pack was designed by HSGI with the input of USMC Scout/Snipers.  It is meant to offer the user a stable shooting platform for long guns, while still providing useful storage area.  The SBP has several methods by which it can be attached to a belt, LBV or pack.  The inside of the pack provides a cargo area that is aprox 8"x11"x6", and is protected by a pack cloth, drawstring storm flap.  A heavy duty zipper on three sides of the lid allows the pack to be fully opened, giving total access to the cargo area.  The shooting supports on top of the pack are designed to cradle the fore end of a rifle so it remains stable.  Changes in elevation can be made by folding a padded flap out of the support channel.  This feature also allows the pack to be fitted with hook and loop material so that it can be rigged for aerial platform shooting.