At the risk of sounding contrary, I have to say that I don't know anyone shooting in BR events locally who uses jam seating but does not pay close attention to neck tension. You still want a good grip on the bearing surface of the bullet; the goal being to seat to jam but move the bullet as little as possible. There are some good posts and articles to be found on the subject on benchrest.com and 6mmBR.com.
"If the enemy is in range, so are you." - Infantry Journal