Heavier BCG reduce recoil?

If a heavier buffer reduces felt recoil, does going from a semi auto carrier to a FA M16 carrier also reduce recoil?

Also other than weight (little more material at the end) is there any difference between a F/A M16 BCG and a Semi Auto BCG?

ETA: can some one explain to me how an extra power spring reduces recoil?

To a small degree, yes. The FA BCG trips the sear, which gives it big bragging rights. Aside from that, the differences are negligible.