Some years back, I talked at length with Jerry. He was setting up to shoot the 10-gun, 60shot speed record at the NRA PPC Nationals at Jackson, MS. I was in the gallery and witnessed the event. He did it three times, and each was faster than the previous run....
I had the opportunity to look at and handle his .38Spl ammo. It was truly unremarkable. Just a "home cast" double end 148gr wadcutter, in mixed brass; nickle plated and plain. He stated he used an unremarkable 2.8-3.0gr of Bullseye. He stated then that he shot 70-100,000rds a year, so casting bullets and loading ammo was just another "chore" that was done with the least expensive and fastest means possible... IIRC; at the time he said he was using a Dillon 1000.
I would expect no different from his .45acp ammo.
With the type of shooting he does, an extreame degree of accuracy isn't demanded. Revolvers only require that the bullet exit the barrel to be reliable, and past a certain point, extra velocity just wears the guns out faster and cost more to produce.
I also got to handle the S&W Model 10's he was shooting. The only remarkable thing about them, is that they were unremarkable !!! The triggers hadn't been worked over and had factory original rebound springs (rather heavy trigger pulls.... so that they pushed the finger back...) Just like Ed McGivorn said in his book 60+yrs earlier ("Fast and Fancy Shooting").
I would expect that he's using something economical yet still effective. IMO, American Select or TiteGroup would sound reasonable. Something that will use a light charge weight but still develope adequate velocity and meter good/consistent through a powder measure. Nothing "magical".... Just whatever "works".
BTW; The secret is his hands..... They're HUGE... He would have been a heavy equipment mechanic if he hadn't become a cop and shooter.... and practice, practice, practice....