I don't know... every gas block that has bonked a rail upon firing has given me poor accuracy and group size. So I am not exactly sure why.
I tend to focus on "precision shooting", over "combat shooting" , so my viewpoint is probably skewed towards that, and minimizing group altering issues.
My apologizes, I tend to forget not everyone has my same perspective about AR's.
Every time I have altered the hand guard and GB contact( replaced , or made sure contact was eliminated ) accuracy ( precision ) has become more consistent.
It might be something as simple as the barrel has stopped wriggling around sooner, or is doing its movement in a more consistent, repeatable manner, prior to the next shot.
So , again I don't know why .. I just try to minimize whip and contact between the parts. It may not be a barrel whip issue at all. It could very well be a "the barrel whip / contact is altering my shooting stance issue" ( In other words a "me" issue )
And I could be completely wrong. I just have found less barrel movement has made my groups consistently better... so minimizing that effect, helps me shoot "better".
Maybe someone can explain better what I mean. ( Or point out what I need to focus on to stop the effect , Lol )
I am not the most articulate guy, so pardon my lack of eloquence ( had to spell check that one )... my experience's tend to dictate my thinking.
So most certainly don't take my experience's as Gospel.
@Yondering And I have to ask.... how do barrel tuners work ? ( Not trying to be flippant , just trying to understand since the bullet will have left the barrel prior to the whip as well )
Adjusting the tuner, also changes the point of impact... so something is altering the whip and bullets exit.
My Browning BAR with its BOSS system most certainly works. It is a PITA , to tune for the various loads , but it does group better after even just using the Brownings suggested settings.
This makes sense to me. There are tons of videos showing a tuners improvements on group size via tuning.