OP - I'm glad it worked!
My Gunar enjoys breaking the cross ties, too. I've found that placing a hay bale directly behind him works like a charm. He stands quietly for as long as I want him to.
"The captive bolt is not a proper tool for slaughter of equids they regain consciousness 30 seconds after being struck fully aware they are being vivisected." Dr Friedlander DVM & frmr Chief USDA Insp