We run a lot of 4340. We always run a Valenite WNMG432 NM6 WPP10 for roughing. We do about .100"- .150" depth of cut at 800 S.F.M. and run at .009"-.013 I.P.R. We get approx 50-80 pieces per edge. We tried Sandvik, Kennametal, and Iscar. They were decent, but the Valenite really excelled. 4340 can really be a pain, and we experimented for a looong time with this material.
You will not be upset with the results if you try the Valenite.
We run one 17-4PH job, but we make a lot of pieces annually. It is a tricky material. I don't take the depth of cut your describing, but I have had great luck with a CNMG 332 (Kennametal brand, can't remember details). I run the SFM around 200-300 and feed up to .01" per rev. What I notice about 17-4 is that the material is not consistent from batch to batch. I have had some stock that ran wonderfully, and some that I had to re-write all the speeds and feeds to get good tool life. Can be tricky. I'd rather have 303 or 316 S.S. than 17-4. It changes a lot.
Good luck to you!
Progressive Turnings, Inc.
www.progressiveturnings.com