Glad to hear that your Sig found the ammo it prefers. That's why I bought 4-5 boxes of different factory stuff before I went in for a brand to inventory 1,000 rounds.
I have around 250 rounds through mine and noticed that the trigger smoothed out a wee bit but my trigger was pretty sweet to begin with. I did lube it a bit with some Tetra lube and that did help. I notice that my son's trigger was not heavy but a bit gritty so we lube that one up too.
My guess is that your trigger will improve with some more rounds down the range. Also I betting that your groups could become continually better with some hand load tuning.
Seems like we now have 3 Sig M400 Enhanced that are shooting 3 shot groups under a inch with factory ammo. Great record.
