The stabiliser will not affect the power no matter how out of adjustment it is.
Remove the reg and put it on a reg checker for 48 hrs to see if it's creeping.
Examine the hammer spring and firing valve spring end's to see if the are square, Polish them until they are like chrome.
Also check to see if the transfer port is leaking.
Let your shooting do the talking.
It's not the aim and release that decided the shot, it's the preparations.