Team Sootch has a simple take on a lightweight sand bag gun rest for range and field use, minus the sand– and walks you through making your own shooting sock.
Starting with shot bags filled with sand and moving up from there, bench rest sandbags and purpose-made beanbags for forearm and stock support are available from just about every shooting parts house you can search on the internet.
A number of accessory makers have really responded to the sand sock concept in recent years and make a wide array of “tactical bean bags” for use to help keep your rifle steady.
Or you can just make your own with the help of some socks and airsoft BBs.
Source Article from http://www.guns.com/2015/09/25/the-diy-shooting-sock-and-why-you-need-one-video/