6.4gr powerpistol and CCI SRP with 180gr Speer gold dot is my go to load.
Out of my G23 with a KKM barrel I get 986 FPS.
Titegroup with a 180 cast is a good plinking load
That's not a typo, I use small rifle primer in my 40, Been doing so for about 10 years to keeps reloading components consolidated and
cost down a little. I shoot IPSC and have tens of thousands of rounds downrange with no misfires
Whatever you do, get a fully supported barrel for those .40s. KKM, Lone Wolf, Stormlake, Bar Sto, etc. all make great barrels and LW starts at around $100.