I had good luck with the BOSS. I also use one load for that gun that works.Browning's BOSS. Supposed to improve accuracy by changing barrel vibration. It could do that, if you only use one load, but the change is very small.
Its a solid concept that does work but the marketing hype made it out to be able to take a 5 MOA gun and turn it into a .25 MOA gun and that's not the case.