Earlier in the week, 72-year-old Rosemary Lenton had set the same record when winning the women's para pairs for Wales in the same sport.
However, on Friday afternoon, 75-year-old Miller succeeded Lenton's new mark as he contributed to Scotland beating Wales by a 16-9 scoreline.
Speaking to BBC Sport, Miller said: "A year ago I never dreamed of being here. I got a phone call, and nearly fell off my chair to be honest. Here we are - where are we going to go from here?!
"Bowls is easier for older people - but any sport, walking football, rugby, you name it. Get out there and exercise, play games, compete. It's brilliant whatever age you are."
Scotland have now won eight golds and a total of 35 medals during the Games, moving them into fifth place in the medal standings. body check tags ::