I use the Speer Gold Dot 135+P SB for carry, in both my 3" M65-3, & my 2.125" M640-1.
Due to the price of this factory fodder, I don't shoot a lot of it - but have found that Dardas 158LSWCs, over 3.6 grains of TiteGroup, WWSP primers, in .357 BRASS, makes a very accurate (a bit better then the 135 Gold Dots, in fact), equivalent target load.
In .38SPL brass, Dardas 158LSWCs, over 3.2 grains of TiteGroup, WWSP primers, seems to be the magic number.
I'm stocked up w/ W231, Unique, VV-N320, VV-N330, & Power Pistol, but the TiteGroup load works so well for target, that I've pretty much quit further experimentation.
That said, I've got an M&P 340 on the ol' bucket list, & if acquired, will probably try to work up a similar target load - utilizing an Xtreme plated bullet. Reason being, I think that residue cleanup from a plated bullet load "might" be a little easier on the alloy revolver's factory coating.