I think you'll be pretty happy with the Missouri bullets, I use them a lot in my 38's.
I would imagine with the 9 cone, due to shape, its a gonna be a little longer than normal. I think my last 124gr load was at around 1.12 I think... I could be wrong.
I think max 9mm OAL is around 1.16, but every gun and bullet will be different, as the OGIVE to Rifling meeting is similar to a rifles.
I would load up a few test rounds with lower charge, seating the bullet exactly halfway between the groove and the start of the ogive, and make sure they function in your mags, and will chamber freely without deformation.
To be honest, I really don't pay attention to OAL from the book. I work up each load to make sure its safe in what I'm shooting, and I don't ever load near the top anyways. Most of the time, with .38's I'm crimping the crimp groove regardless so who cares. With 9mm, you're not doing a roll crimp, so you have more flexibility.
I load the 125 Cone exclusively in a 320 X5. No feed issues whatsoever at 1.100 OAL. Currently loading 4.0 AA No. 2 or 3.8 Titegroup. Have loaded Power Pistol but it seems to perform best at higher velocity than I need for IDPA. Have 3k on backorder and they’re really busy, as you can imagine.
I will plunk test each pistol with dummy rounds. Start out long, adjust as needed. For liability reasons I won't use handholds in my carry pistol. As a police officer in the early 70's I routinely carried handloads, not so much for added velocity but for penetration. I cast my own 357mag hardcast 158gr swc bullets. Never shot anyone with those loads but stopped a couple vehicles shooting through steel rims & radiators.
Thanks 308 pirate for the helpful info.