I designed a 3D printable bi-pod system to go on my tip-man paintball gun. However this bi-pod will fit most barrels with its adjustable barrel clamp. 

To assemble you will need 1/2 inch tubing (preferred to be flexible), 6 #10 UNC24 nuts, 4 #10 UNC 1/2 Inch bolts, and 2 #10 UNC 1Inch bolts. Also to minimize turning of the bi-pod use electrical tape around the area of the barrel before clamping on the bi-pod. if you have issues with the bipod legs comind undone use thread lock in the bolts for the legs to the clamp. 

Have fun