My BCG is 18.1oz un-weighted... but 22.1oz weighted.
So we are talking 4 full oz
I am using a Tubbs CWS (Carrier Weight System)
Tubb AR 15 CWS Bolt Carrier Weight System
I went this direction before before rojodiablo suggested an increase in buffer weight:
M&P 10 Short Stroking
both solutions will slow down the action and smooth out the recoil cycle.
I can't speak for the buffer weight increase, but the added weight in the BCG dramatically reduces the felt recoil. So much, that when in my RRA AR15, its recoil amounts to a slightly stouter .22 long rifle... and I am not exaggerating
Another change that would change the cycling properties would be an adjustable gas block. I may play with that this spring