If you push a PB through your barrel with the breech out some of the bullets will not have even rifling marks all the way around. Some of them don't mic to .50 so that being said is a reason some people don't get good accuracy.
I'm glad they work for you but I suspect some of your results like everyone getting 2in groups at 100yds?
I believe most gun shops push PB's for other reasons and they have a huge ad compaign compared to other manufactures.