Daid Tubb participated in the game at a time when there was more experimentation with equipment, etc. This, along with better resources allowed his creative mind to experiment and develop innovative approaches to shooting.
David first developed what came to be know as "chin guns" by developing offset, ultra-high scome mounting systems designe to keep the shooter's head as straight as posibble and to utilize as much of the shooter's skeletal structureas possible to hold the rifle. Using such a system, a shooter would place his or her elbow on the hip bone and rest the chin on the comb of the rifle (thus the name "chin gun). This produced a very stable stance. Eventually, the "chin gun" set-up was disallowed. This still required immense talent for anyone to accomplish what David did.
I met David Tubb in New Braunfels, Texas, many years ago when the "chin gun" was still legal and he actually let me shoot his. If I remember correctly, the rifle, other than the scope-mounting system, was a Remington 700 action in 7mm-08 equipped with a light-pull Canjar trigger (It may have been a Kenyon), a reverse taper barrel and an extra strong firing pin spring. For hunter rifle, David shot Reminton M-700 rifles with no more than a good glass bedding and a trigger job.
Every generation brings an outstanding silhouette shooter. In the 80's it was David Tubb. Agustin is this generation's star shooter.