Barrel tuners are pretty 'old tech'.
They have been around in one form or another since at least the 1940's and have had their occasional periods of popularity with target shooters.
Some shooters love them while other shooters think they are a useless appendage to a rifle.
I think it's time for something new, something like Peter Brock's energy polarizer attached to your barrel which will "align the molecules" of your barrel thereby making it shoot straighter and sweeter and make your cartridge more powder efficient.
And remember it was invented here in Australia!