I hate to disagree...but simple physics state that
Force = Mass * Acceleration

With the advent of the newer loads, such as Hevi-shot and X-tended range, the force delivered from their #6 shot is almost equivalent to the force delivered from copper-plated or straight lead. Why? Simple...increased acceleration, coupled with a denser pattern. Hence, the center of mass is denser & more compact, delivering the same force.

Hey Boss...the 20+ pound gobbler I took at 45 yards this Spring will beg to differ with your dismay at long shots with #6.

But alas, I will also agree. I do not like to take shots longer than 35 yards with #6. I harvested that bird in an open clearing, where there was no chance for shot deflection or scatter.

Back to topic. I always shot the Win Supremes, and in my Ithaca found that the Win X-tended patterned much better/consistent than the Rem Hevi.