I realize after re-reading that I hadn't made one thing clear: I replaced the Wolff 15# recoil spring (which only had some 500 rounds logged on it since its installation) in my SIG GSR with a BH Spring Solutions' 16# after testing both; I found the BH Spring Solution 16# provided greater consistency withing th 4'-8' guideline; basic pattern with it was empty cases ejecting 6'.
Best, Jon