Patriot.  The Patriot was an early'90s model two-tube blow-back. Like the PMI-III/VM-68, it's unique among blow-backs in having a large diameter main spring in the top tube. Also like those guns, the heavy internal parts give the gun a noticable (for a paintball gun) kick and a loud report. It is also the only blow-back I have seen which features a velocity adjuster in the hammer.  The bottomline adapter is actually welded onto the .45 grip frame. The gun has a heavy trigger pull by today's standard's, but shoots really well. The gun was made by a company called Ultrasport Inc. of Racine Wisconsin. I recently found an ad in a 1992 issue of Action Pursuit Games showing the gun retailed for $359.