Last time I had the fun-sucker out (my nickname for my chrono... which bleeds fun out of range days...), my most often used very late model 52-2 (TZT-prefix) gave me two different results:

148gr old old stock Star swaged HBWC over 2.7gr Bullseye returned a 718 fps average for 10 shots

And...
New manufacure Precision Delta 148gr swaged HBWC over 2.8gr Bullseye gave me 750 fps average for 10 shots

NOTICE that you cannot come to a dead-firm conclusion on the one-tenth grain powder difference because I was using two different, albeit similarly designed bullets.