I don't think there is any design approved or disapproved. Some older ranges still have wooden benches/legs. If benches are not stable, shooters would probably not show up, or spend their day b!tching about them.
I bought Bore Tech rods when they came out, and after a short time the coating came off. I called them, they would not replace them. Never again. I have a pair of coated Dewey's that are close to 30 years old and the coating is still there.
I shot a 6.5/06AI in long range for a while, and I used 30/06 brass. Necked them down then ran them in the 6.5/06AI sizer until I had a snug bolt close. Then fire formed.
Well, there are many top shooters shooting RR guns. I've never seen where they were handicapped by it. You get one of those cartridge holders sitting right next to the loading port, and with an ejector, you can be just as fast.
I don't know the rules of World Championships, evidently they don't care about barrel taper. But anyone from this country with a HV gun will have a tapered barrel.