Tungsten Alloy Bucking bars weighs almost twice as much as conventional steel which makes it a perfect material for manufacturing a small yet HEAVY Bucking Bar. As you know, the heavier the bar, the easier it is to shoot your rivet.
This specially designed bucking bar is required on the Van's Aircraft RV-10 and RV-14 for riveting inside the elevators. The bar dimensions are call out in the RV builders plans pages 9-12 of the control surface section.