I'm wanting to purchase and mount a holosun 507k onto a P365XL and was wondering if milling would get the optic lower or is the factory cutout as low as possible.

Lowest is the priority but factory cutout would be easiest.

Thanks...

The gun is already optic cut and I believe no plate is needed. Mount directly to slide.

As Com 45acp stated, the XL slide is already factory cut and the Holosun 507K mounts directly to it.

And the rear notch on the 507K works fine with the factory front sight. No need to go lower.

Awesome, I appreciate the input. Happy Independence Day.

Concur with everybody else.