Blue water big game guns back in the other century like the 90's of Steve Alexander and Riffe were 3/8 diameter shaft and 72 inches long . Even though Steve had his own personal gun with a whooping 1/2 inch diameter shaft , this is my sole idea of mine that has never seen the day of light . A 3/8 diameter shaft with a length of 72 inches weights in at 2.056 pounds and a 1/2 inch diameter shaft with a length of 36 inches weighs in at 2.004 pounds . Guess what , yea making a three foot big game gun seems worthy to investigate . Using the double roller from the past should power this 1/2 inch shaft . Who would like to develop this hybrid of a big game gun with the old and new in mine. Be Good ,Safe and kind Rumdumb