Whelen was a colonel in the United States Army, contributing editor to Sports Afield, American Rifleman, Field and Stream, Outdoor Life, Guns & Ammo, and other magazines, and author of Telescopic Rifle Sights, The Hunting Rifle, Small Arms and Ballistics, Hunting Big Game, and Why Not Load Your Own. An autobiography, Mr. Rifleman, was begun by Whelen, but finished by his family and published after his death. An expert rifleman with few peers, Whelen could reportedly hit man-sized target at 200 yards using the bolt action, open-sighted M1903 Springfield .30-06 service rifle, scoring six hits in ten seconds flat, and could do it on command.
Colonel Whelen experimented with the service .30-06 Springfield cartridge while he was commanding officer of Frankford Arsenal in the early 1920s. Frankford Arsenal machine shop foreman James Howe, who later formed the rifle-making firm of Griffin & Howe, assisted Whelen modifying the .30-06 case to fire bullets of different calibers. Whelen was particularly interested in creating a cartridge to fire heavier bullets from M1903 rifle actions available from the Civilian Marksmanship Program.
- "Only accurate rifles are interesting".
- "The .30-06 is never a mistake".
- Petzal, David E. (6 June 2006). "Great American Hunters: Townsend Whelen". Field and Stream. Retrieved 30 November 2011.
- Folkerth, Mike (29 August 2008). "The Wisdom of Col. Townsend Whelen". Mike Folkerth - King of Simple. Retrieved 30 November 2011.
- Rocketto, Hap (July 2010). "Townsend Whelen: Mister Rifleman". The Rifleman's Journal (formerly by The Shooter's Journal). Retrieved 30 November 2011.
- Sharpe, Philip B. (1953). Complete Guide to Handloading; A Treatise on Handloading for Pleasure, Economy, and Utility (2nd revision, 3rd ed.). New York: Funk & Wagnalls. pp. 206 & 398. OCLC 627391.