I am new to all of this and I hope I can state my question adequately.
In reading some of the posts, it appears that power factor (PF) can vary significantly with different ammo. I am not so much concerned about the minimum PF that may be required for competitive shooting, I am simply wondering if there is a specified PF range to be used in the M&P Pro 9mm? Perhaps more to the point, is there a minimum and/or maximum PF that can be safely used in this firearm?
Thank you in advance for any guidance that may be provided.

Standard factory ammo should be fine in your gun. Ammo labeled +p or ++P have more umph. Personally I don't see the need to shoot ammo that is +P or higher. That is just my opinion. But your standard factory ammo should be just fine. Personally, for factory ammo I like PMC, American Eagle and Federal. They are inexpensive, shoot well, and I have never had an issue with them.

Thank you. It is always helpful to know of others' experiences.

Factory ammo should be fine to meet IDPA and USPSA Production or Limited minor power factor... especially the 147 and 124 grain versions. I wouldn't use the pistol for Open major but it's unlikely that's the direction you were thinking of going at this point.

Part of the answer depends on who is holding the gun. A wimp grip combined with wimp ammo is safe, but does not feed and eject smartly. A PF below 130 starts to show 2 problems: weak ejection and accuracy falls off. So if you meet minor PF 135, you're fine.
On the high side, if you start loading hot, like pushing PF 150, you could use a little more spring.
A quick check is to look where the empties land: 3 to 6ft away is fine.
If the case dribbles out, you're weak.
If the case goes zinging across the range, either lighten the powder charge or put in more spring.

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